Copyright (c) 1998 Association of Mizar Users
environ vocabulary ARYTM, COMPLEX1, COMSEQ_1, SEQ_1, FDIFF_1, ARYTM_3, ARYTM_1, FUNCT_1, RELAT_1, QC_LANG1, PREPOWER, SERIES_1, ABSVALUE, RLVECT_1, SEQM_3, SEQ_2, SUPINF_2, ORDINAL2, PROB_1, SQUARE_1, PARTFUN1, INCSP_1, RCOMP_1, PRE_TOPC, BOOLE, FCONT_1, SUBSET_1, SIN_COS, FINSEQ_4, GROUP_1; notation TARSKI, XBOOLE_0, SUBSET_1, ORDINAL1, NUMBERS, ARYTM_0, XCMPLX_0, XREAL_0, REAL_1, FUNCT_1, FCONT_1, FUNCT_2, SEQ_1, SEQ_2, FDIFF_1, RELAT_1, SERIES_1, ABSVALUE, NAT_1, FINSEQ_4, NEWTON, COMPLEX1, SQUARE_1, PREPOWER, PARTFUN1, SEQM_3, RCOMP_1, BINARITH, RFUNCT_1, RFUNCT_2, COMSEQ_1, COMSEQ_2, COMSEQ_3; constructors COMSEQ_3, REAL_1, SEQ_2, RCOMP_1, FINSEQ_4, FCONT_1, RFUNCT_1, FDIFF_1, SQUARE_1, COMSEQ_1, COMSEQ_2, PREPOWER, SERIES_1, PARTFUN1, BINARITH, RFUNCT_2, COMPLEX1, MEMBERED, ARYTM_0, ARYTM_3, FUNCT_4; clusters INT_1, COMSEQ_2, COMSEQ_3, XREAL_0, RELSET_1, FDIFF_1, RCOMP_1, SEQ_1, COMSEQ_1, SEQM_3, NEWTON, COMPLEX1, MEMBERED, ORDINAL2, NUMBERS; requirements REAL, NUMERALS, SUBSET, BOOLE, ARITHM; definitions COMSEQ_3; theorems AXIOMS, NAT_1, REAL_1, ABSVALUE, REAL_2, INT_1, SEQ_1, SEQ_2, SERIES_1, SEQM_3, SEQ_4, PREPOWER, COMPLEX1, COMSEQ_1, COMSEQ_2, SQUARE_1, COMSEQ_3, FCONT_2, FINSEQ_4, RCOMP_1, FUNCT_1, FDIFF_1, FDIFF_2, FCONT_1, FCONT_3, TARSKI, FUNCT_2, RFUNCT_1, SUBSET_1, RFUNCT_2, RELSET_1, POWER, PARTFUN1, ROLLE, NEWTON, RELAT_1, XREAL_0, JORDAN6, TOPREAL5, SCMFSA_7, GOBOARD9, XBOOLE_0, XBOOLE_1, XCMPLX_0, XCMPLX_1, ARYTM_0; schemes NAT_1, SEQ_1, COMSEQ_1, RECDEF_1, FUNCT_1, PARTFUN2, COMPLSP1; begin reserve p,q,th,th1,th2,th3,r for Real, w,z,z1,z2 for Element of COMPLEX, k,l,m,n,n1,n2 for Nat, seq,seq1,seq2,cq1 for Complex_Sequence, rseq,rseq1,rseq2 for Real_Sequence, rr for set, hy1 for convergent_to_0 Real_Sequence; Lm1: (for x, y be real number st x <y holds (for a be real number st a>0 holds (a * x < a * y & x/a < y/a)) ) & (for x, y be real number st x < y & 0 < x holds 1 < y/x) proof now let x, y be real number such that A1: x <y; let a be real number; assume a>0; hence a * x < a * y & x/a < y/a by A1,REAL_1:70,73; end; hence thesis by REAL_2:142; end; Lm2:now let n; 0 <= n by NAT_1:18; hence 0 < n+1 by NAT_1:38; end; ::Some definitions and properties of complex sequence definition let m,k be Nat; canceled; func CHK(m,k) -> Element of COMPLEX equals :Def2: 1r if m <= k otherwise 0c; correctness; func RHK(m,k) equals :Def3: 1 if m <= k otherwise 0; correctness; end; definition let m,k be Nat; cluster RHK(m,k) -> real; coherence proof m <= k or m > k; hence thesis by Def3; end; end; definition let m,k be Nat; redefine func RHK(m,k) -> Real; coherence by XREAL_0:def 1; end; scheme ExComplex_CASE{F(Nat,Nat)->Element of COMPLEX}: for k holds ex seq st for n holds ((n <= k implies seq.n=F(k,n)) & (n > k implies seq.n=0c)) proof let k; defpred P[set,set] means ex n st (n=$1 & (n <= k implies $2=F(k,n )) & (n > k implies $2=0c) ); A1: now let x be set; assume x in NAT; then consider n such that A2: n=x; A3: now assume n <= k; hence CHK(n,k) * F (k,n) =1r * F(k,n) by Def2 .=F(k,n) by COMPLEX1:29; end; A4: now assume n > k; hence CHK(n,k) * F (k,n) =0c * F(k,n) by Def2 .=0c by COMPLEX1:28; end; reconsider y=CHK(n,k) * F (k,n) as set; take y; thus P[x,y] by A2,A3,A4; end; A5: for x,y,z be set st x in NAT & P[x,y] & P[x,z] holds y=z; consider f be Function such that A6: dom f =NAT and A7: for x be set st x in NAT holds P[x,f.x] from FuncEx(A5,A1); now let x be set; assume x in NAT; then ex n st (n=x & (n <= k implies f.x=F(k,n)) & (n > k implies f.x=0c)) by A7; hence f.x is Element of COMPLEX; end; then reconsider f as Complex_Sequence by A6,COMSEQ_1:1; take seq=f; let n; ex l be Nat st l=n & (l <= k implies seq.n=F(k,l)) & (l > k implies seq.n=0c) by A7; hence ((n <= k implies seq.n=F(k,n)) & (n > k implies seq.n=0c)); end; scheme ExReal_CASE{F(Nat,Nat)->real number}: for k holds ex rseq st for n holds ((n <= k implies rseq.n=F(k,n)) & (n > k implies rseq.n=0)) proof let k; defpred P[set,set] means ex n st (n=$1 & (n <= k implies $2=F(k,n )) & (n > k implies $2=0) ); A1: now let x be set; assume x in NAT; then consider n such that A2: n=x; A3: now assume n <= k; hence RHK(n,k ) * F (k,n) =1 * F(k,n) by Def3 .=F(k,n); end; A4: now assume n > k; hence RHK(n,k) * F (k,n) =0 * F(k,n) by Def3 .=0; end; reconsider y=RHK(n,k) * F (k,n) as set; take y; thus P[x,y] by A2,A3,A4; end; A5: for x,y,z be set st x in NAT & P[x,y] & P[x,z] holds y=z; consider f be Function such that A6: dom f =NAT and A7: for x be set st x in NAT holds P[x,f.x] from FuncEx(A5,A1); now let x be set; assume x in NAT; then ex n st (n=x & (n <= k implies f.x=F(k,n)) & (n > k implies f.x=0)) by A7; hence f.x is real; end; then reconsider f as Real_Sequence by A6,SEQ_1:3; take rseq=f; let n; ex l be Nat st l=n & (l <= k implies rseq.n=F(k,l)) & (l > k implies rseq.n=0) by A7; hence ((n <= k implies rseq.n=F(k,n)) & (n > k implies rseq.n=0)); end; definition func Prod_complex_n -> Complex_Sequence means :Def4: it.0 = 1r & for n holds it.(n+1) = it.n * [*(n+1),0*]; existence proof deffunc U(Nat,Element of COMPLEX) = $2 * [*$1+1,0*]; consider f being Function of NAT,COMPLEX such that A1: f.0 = 1r & for n being Nat holds f.(n+1) = U(n,f.n) from LambdaRecExD; reconsider f as Complex_Sequence; take f; thus thesis by A1; end; uniqueness proof let seq1,seq2; assume that A2: seq1.0=1r & for n holds seq1.(n+1)=seq1.n * [*(n+1),0*] and A3: seq2.0=1r & for n holds seq2.(n+1)=seq2.n * [*(n+1),0*]; defpred X[Nat] means seq1.$1 = seq2.$1; A4: X[0] by A2,A3; A5: for k be Nat st X[k] holds X[k+1] proof let k be Nat; assume seq1.k =seq2.k; hence seq1.(k+1) = seq2.k * [*(k+1),0*] by A2 .= seq2.(k+1) by A3; end; for n holds X[n] from Ind(A4,A5); hence seq1 = seq2 by COMSEQ_1:6; end; end; definition func Prod_real_n -> Real_Sequence means :Def5: it.0 = 1 & for n holds it.(n+1) = it.n * (n+1); existence proof deffunc U(Nat,Element of REAL) = $2 * ($1+1); consider f being Function of NAT,REAL such that A1: f.0 = 1 & for n being Nat holds f.(n+1) = U(n,f.n) from LambdaRecExD; reconsider f as Real_Sequence; take f; thus thesis by A1; end; uniqueness proof let rseq1,rseq2; assume that A2: rseq1.0=1 & for n holds rseq1.(n+1)=rseq1.n * (n+1) and A3: rseq2.0=1 & for n holds rseq2.(n+1)=rseq2.n * (n+1); defpred X[Nat] means rseq1.$1 = rseq2.$1; A4: X[0] by A2,A3; A5: for k be Nat st X[k] holds X[k+1] proof let k be Nat; assume rseq1.k =rseq2.k; hence rseq1.(k+1) = rseq2.k * (k+1) by A2 .= rseq2.(k+1) by A3; end; for n holds X[n] from Ind(A4,A5); hence rseq1 = rseq2 by FUNCT_2:113; end; end; definition let n be Nat; func n !c -> Element of COMPLEX equals :Def6: Prod_complex_n.n; correctness; end; definition let n be Nat; redefine func n! -> Real equals :Def7: Prod_real_n.n; coherence by XREAL_0:def 1; compatibility proof defpred X[Nat] means Prod_real_n.$1 = $1!; A1: X[0] by Def5,NEWTON:18; A2: now let l be Nat; assume A3: X[l]; Prod_real_n.(l+1) = Prod_real_n.l * (l+1) by Def5 .= (l+1)! by A3,NEWTON:21; hence X[l+1]; end; for k be Nat holds X[k] from Ind(A1,A2); hence thesis; end; end; definition let z be Element of COMPLEX; deffunc U(Nat) = z #N $1 /($1!c); func z ExpSeq -> Complex_Sequence means :Def8: for n holds it.n = z #N n /(n!c); existence proof thus ex s being Complex_Sequence st for n holds s.n = U(n) from ExComplexSeq; end; uniqueness proof thus for s1,s2 being Complex_Sequence st (for x being Nat holds s1.x = U(x)) & (for x being Nat holds s2.x = U(x)) holds s1 = s2 from FuncDefUniq; end; end; definition let a be real number; deffunc U(Nat) = a |^ $1 /($1!); func a ExpSeq -> Real_Sequence means :Def9: for n holds it.n = a |^ n /(n!); existence proof thus ex s being Real_Sequence st for n holds s.n = U(n) from ExRealSeq; end; uniqueness proof thus for s1,s2 being Real_Sequence st (for x being Nat holds s1.x = U(x)) & (for x being Nat holds s2.x = U(x)) holds s1 = s2 from FuncDefUniq; end; end; theorem Th1: (0 < n implies [*n,0*] <> 0c) & 0!c = 1r & n!c <> 0c & (n+1)!c = n!c * [*n+1,0*] proof thus 0 < n implies [*n,0*] <> 0c proof assume A1:0 <n; assume [*n,0*] = 0c; hence contradiction by A1,COMPLEX1:7,12; end; defpred X[Nat] means $1!c <> 0c; thus 0!c = Prod_complex_n.0 by Def6 .= 1r by Def4; then A2: X[0] by COMPLEX1:133,134; A3: now let n; assume A4: X[n]; A5: (n+1)!c = Prod_complex_n.(n+1) by Def6 .= Prod_complex_n.n * [*n+1,0*] by Def4 .= n!c * [*n+1,0*] by Def6; [*n+1,0*] <> 0c by COMSEQ_3:1; hence X[n+1] by A4,A5,XCMPLX_1:6; end; for n holds X[n] from Ind(A2,A3); hence n!c <> 0c; thus (n+1)!c = Prod_complex_n.(n+1) by Def6 .= Prod_complex_n.n * [*n+1,0*] by Def4 .= n!c * [*n+1,0*] by Def6; end; theorem n! <> 0 & (n+1)! = n! * (n+1) by NEWTON:21,23; theorem Th3: (for k st 0 < k holds ((k-'1)!c ) * [*k,0*] = k!c) & for m,k st k <= m holds ((m-'k)!c ) * [*(m+1-k),0*] = (m+1-'k)!c proof A1: now let k; assume 0 < k; then 0+1 <= k by INT_1:20; then k-'1+1=k-1+1 by SCMFSA_7:3 .=k by XCMPLX_1:27; hence k!c =(k-'1)!c * [*k,0*] by Th1; end; now let m,k such that A2: k <= m; m <= m+1 by REAL_1:69; then k <= m+1 by A2,AXIOMS:22; then m+1-'k=m+1-k by SCMFSA_7:3 .=m-k+1 by XCMPLX_1:29 .=m-'k+1 by A2,SCMFSA_7:3; hence (m+1-'k)!c=((m-'k)!c ) * [*(m-'k)+1,0*] by Th1 .=((m-'k)!c ) * [*m-k+1,0*] by A2,SCMFSA_7:3 .=((m-'k)!c ) * [*m+1-k,0*] by XCMPLX_1:29; end; hence thesis by A1; end; definition let n be Nat; func Coef(n) -> Complex_Sequence means :Def10: for k be Nat holds (k <= n implies it.k = n!c /( (k!c ) * ((n-'k)!c ))) &(k > n implies it.k=0c); existence proof deffunc U(Nat,Nat) = $1!c /( ($2!c ) * (($1-'$2)!c)); for n holds ex seq st for k holds (k <= n implies seq.k = U(n,k)) & (k > n implies seq.k=0c ) from ExComplex_CASE; hence ex seq st for k holds (k <= n implies seq.k = n!c /( (k!c ) * ((n-'k)!c))) & (k > n implies seq.k=0c); end; uniqueness proof let seq1,seq2; assume that A1: for k holds (k <= n implies seq1.k = n!c /( (k!c ) * ((n-'k)!c))) & (k > n implies seq1.k=0c) and A2: for k holds (k <= n implies seq2.k = n!c /( (k!c ) * ((n-'k)!c))) & (k > n implies seq2.k=0c); now let k; per cases; suppose A3:k <= n; hence seq1.k = n!c /( (k!c ) * ((n-'k)!c)) by A1 .= seq2.k by A2,A3; suppose A4:k > n; hence seq1.k = 0c by A1 .= seq2.k by A2,A4; end; hence seq1=seq2 by COMSEQ_1:6; end; end; definition let n be Nat; func Coef_e(n) -> Complex_Sequence means :Def11: for k be Nat holds (k <= n implies it.k = 1r/((k!c ) * ((n-'k)!c ))) & (k > n implies it.k=0c); existence proof deffunc U(Nat,Nat) = 1r/(($2!c ) * (($1-'$2)!c )); for n holds ex seq st for k holds (k <= n implies seq.k = U(n,k)) & (k > n implies seq.k=0c) from ExComplex_CASE; hence ex seq st for k holds (k <= n implies seq.k = 1r/((k!c ) * ((n-'k)!c ))) & (k > n implies seq.k=0c); end; uniqueness proof let seq1,seq2; assume that A1:for k holds (k <= n implies seq1.k = 1r/((k!c ) * ((n-'k)!c ))) & (k > n implies seq1.k=0c) and A2: for k holds (k <= n implies seq2.k = 1r/((k!c ) * ((n-'k)!c ))) & (k > n implies seq2.k=0c); now let k; per cases; suppose A3:k <= n; hence seq1.k =1r/((k!c ) * ((n-'k)!c )) by A1 .= seq2.k by A2,A3; suppose A4:k > n; hence seq1.k = 0c by A1 .= seq2.k by A2,A4; end; hence seq1=seq2 by COMSEQ_1:6; end; end; definition let seq; func Sift seq -> Complex_Sequence means :Def12: it.0=0c & for k be Nat holds it.(k+1) = seq.k; existence proof deffunc U(Nat,Element of COMPLEX) = seq.$1; consider f being Function of NAT,COMPLEX such that A1: f.0 = 0c & for n being Nat holds f.(n+1)=U(n,f.n) from LambdaRecExD; reconsider f as Complex_Sequence; take f; thus thesis by A1; end; uniqueness proof let seq1,seq2; assume that A2: seq1.0=0c & for n holds seq1.(n+1)=seq.n and A3: seq2.0=0c & for n holds seq2.(n+1)=seq.n; defpred X[Nat] means seq1.$1 = seq2.$1; A4: X[0] by A2,A3; A5: for k be Nat st X[k] holds X[k+1] proof let k be Nat; assume seq1.k =seq2.k; thus seq1.(k+1) = seq.k by A2 .= seq2.(k+1) by A3; end; for n holds X[n] from Ind(A4,A5); hence seq1 = seq2 by COMSEQ_1:6; end; end; definition let n; let z,w be Element of COMPLEX; func Expan(n,z,w) -> Complex_Sequence means :Def13: for k be Nat holds ( k <= n implies it.k=((Coef(n)).k) * (z #N k) * (w #N (n-'k)) ) & (n < k implies it.k=0c); existence proof deffunc U(Nat,Nat) = ((Coef($1)).$2) * (z #N $2) * (w #N ($1-'$2)); for n holds ex seq st for k holds (k <= n implies seq.k = U(n,k)) & (k > n implies seq.k=0c) from ExComplex_CASE; hence ex seq st for k holds (k <= n implies seq.k =((Coef(n)).k) * (z #N k) * (w #N (n-'k))) & (k > n implies seq.k=0c); end; uniqueness proof let seq1,seq2; assume that A1:for k holds (k <= n implies seq1.k =((Coef(n)).k) * (z #N k) * (w #N (n-'k)))& (k > n implies seq1.k=0c) and A2:for k holds (k <= n implies seq2.k = ((Coef(n)).k) * (z #N k) * (w #N (n-'k)) )& (k > n implies seq2.k=0c); now let k; per cases; suppose A3:k <= n; hence seq1.k =((Coef(n)).k) * (z #N k) * (w #N (n-'k)) by A1 .= seq2.k by A2,A3; suppose A4:k > n; hence seq1.k = 0c by A1 .= seq2.k by A2,A4; end; hence seq1=seq2 by COMSEQ_1:6; end; end; definition let n; let z,w be Element of COMPLEX; func Expan_e(n,z,w) -> Complex_Sequence means :Def14: for k be Nat holds ( k <= n implies it.k=((Coef_e(n)).k) * (z #N k) * (w #N (n-'k)) ) & (n < k implies it.k=0c); existence proof deffunc U(Nat,Nat) = ((Coef_e($1)).$2) * (z #N $2) * (w #N ($1-'$2)); for n holds ex seq st for k holds (k <= n implies seq.k = U(n,k)) & (k > n implies seq.k=0c) from ExComplex_CASE; hence ex seq st for k holds (k <= n implies seq.k =((Coef_e(n)).k) * (z #N k) * (w #N (n-'k)) ) & (k > n implies seq.k=0c); end; uniqueness proof let seq1,seq2; assume that A1: for k holds (k <= n implies seq1.k =((Coef_e(n)).k) * (z #N k) * (w #N (n-'k)) ) & (k > n implies seq1.k=0c) and A2:for k holds (k <= n implies seq2.k = ((Coef_e(n)).k) * (z #N k) * (w #N (n-'k)) ) & (k > n implies seq2.k=0c); now let k; per cases; suppose A3:k <= n; hence seq1.k =((Coef_e(n)).k) * (z #N k) * (w #N (n-'k)) by A1 .= seq2.k by A2,A3; suppose A4:k > n; hence seq1.k = 0c by A1 .= seq2.k by A2,A4; end; hence seq1=seq2 by COMSEQ_1:6; end; end; definition let n; let z,w be Element of COMPLEX; func Alfa(n,z,w) -> Complex_Sequence means :Def15: for k be Nat holds ( k <= n implies it.k= (z ExpSeq).k * Partial_Sums(w ExpSeq).(n-'k) ) & ( n < k implies it.k=0c); existence proof deffunc U(Nat,Nat) = (z ExpSeq).$2 * Partial_Sums(w ExpSeq).($1-'$2); for n holds ex seq st for k holds (k <= n implies seq.k = U(n,k)) & (k > n implies seq.k=0c ) from ExComplex_CASE; hence ex seq st for k holds (k <= n implies seq.k =(z ExpSeq).k * Partial_Sums(w ExpSeq).(n-'k) ) & (k > n implies seq.k=0c); end; uniqueness proof let seq1,seq2; assume that A1: for k holds (k <= n implies seq1.k = (z ExpSeq).k * Partial_Sums(w ExpSeq).(n-'k) ) & (k > n implies seq1.k=0c) and A2: for k holds (k <= n implies seq2.k = (z ExpSeq).k * Partial_Sums(w ExpSeq).(n-'k) ) & (k > n implies seq2.k=0c); now let k; per cases; suppose A3:k <= n; hence seq1.k = (z ExpSeq).k * Partial_Sums(w ExpSeq).(n-'k) by A1 .= seq2.k by A2,A3; suppose A4:k > n; hence seq1.k = 0c by A1 .= seq2.k by A2,A4; end; hence seq1=seq2 by COMSEQ_1:6; end; end; definition let a,b be real number; let n be Nat; func Conj(n,a,b) -> Real_Sequence means for k be Nat holds ( k <= n implies it.k= (a ExpSeq).k * (Partial_Sums(b ExpSeq).n -Partial_Sums(b ExpSeq).(n-'k))) & (n < k implies it.k=0); existence proof deffunc U(Nat,Nat) = (a ExpSeq).$2 * (Partial_Sums(b ExpSeq).$1 -Partial_Sums(b ExpSeq).($1-'$2)); for n holds ex rseq st for k holds (k <= n implies rseq.k = U(n,k) ) & (k > n implies rseq.k=0) from ExReal_CASE; hence ex rseq st for k holds (k <= n implies rseq.k =(a ExpSeq).k * (Partial_Sums(b ExpSeq).n -Partial_Sums(b ExpSeq).(n-'k))) & (k > n implies rseq.k=0); end; uniqueness proof let rseq1,rseq2; assume that A1:for k holds (k <= n implies rseq1.k =(a ExpSeq).k * (Partial_Sums(b ExpSeq).n -Partial_Sums(b ExpSeq).(n-'k)) ) & (k > n implies rseq1.k=0) and A2:for k holds (k <= n implies rseq2.k = (a ExpSeq).k * (Partial_Sums(b ExpSeq).n -Partial_Sums(b ExpSeq).(n-'k)) ) & (k > n implies rseq2.k=0); now let k; per cases; suppose A3:k <= n; hence rseq1.k =(a ExpSeq).k * (Partial_Sums(b ExpSeq).n -Partial_Sums(b ExpSeq).(n-'k)) by A1 .= rseq2.k by A2,A3; suppose A4:k > n; hence rseq1.k = 0 by A1 .= rseq2.k by A2,A4; end; hence rseq1=rseq2 by FUNCT_2:113; end; end; definition let z, w be Element of COMPLEX; let n be Nat; func Conj(n,z,w) -> Complex_Sequence means :Def17: for k be Nat holds ( k <= n implies it.k= (z ExpSeq).k * (Partial_Sums(w ExpSeq).n -Partial_Sums(w ExpSeq).(n-'k))) & (n < k implies it.k=0c); existence proof deffunc U(Nat,Nat) = (z ExpSeq).$2 * (Partial_Sums(w ExpSeq).$1 -Partial_Sums(w ExpSeq).($1-'$2)); for n holds ex seq st for k holds (k <= n implies seq.k = U(n,k) ) & (k > n implies seq.k=0c) from ExComplex_CASE; hence ex seq st for k holds (k <= n implies seq.k =(z ExpSeq).k * (Partial_Sums(w ExpSeq).n -Partial_Sums(w ExpSeq).(n-'k)) ) & (k > n implies seq.k=0c); end; uniqueness proof let seq1,seq2; assume that A1:for k holds (k <= n implies seq1.k =(z ExpSeq).k * (Partial_Sums(w ExpSeq).n -Partial_Sums(w ExpSeq).(n-'k)) ) & (k > n implies seq1.k=0c) and A2: for k holds (k <= n implies seq2.k = (z ExpSeq).k * (Partial_Sums(w ExpSeq).n -Partial_Sums(w ExpSeq).(n-'k)) )& (k > n implies seq2.k=0c); now let k; per cases; suppose A3:k <= n; hence seq1.k =(z ExpSeq).k * (Partial_Sums(w ExpSeq).n -Partial_Sums(w ExpSeq).(n-'k)) by A1 .= seq2.k by A2,A3; suppose A4:k > n; hence seq1.k = 0c by A1 .= seq2.k by A2,A4; end; hence seq1=seq2 by COMSEQ_1:6; end; end; Lm3: for p1,p2,g1,g2 being Element of REAL holds [*p1,g1*]+[*p2,g2*] =[*p1+p2,g1+g2*] & [*p1,g1*]-[*p2,g2*] =[*p1-p2,g1-g2*] &[*p1,g1*]*[*p2,g2*] =[* p1*p2-g1*g2,p1*g2+p2*g1 *] & -[*p2,g2*]=[*-p2,-g2*] & [*p2,g2*]*'=[*p2,-g2*] proof let p1,p2,g1,g2 be Element of REAL; A1:Re([*p1,g1*])=p1 & Im([*p1,g1*])=g1 by COMPLEX1:7; A2:Re([*p2,g2*])=p2 & Im([*p2,g2*])=g2 by COMPLEX1:7; thus [*p1,g1*]+[*p2,g2*]=[*Re([*p1,g1*])+Re([*p2,g2*]), Im([*p1,g1*])+Im([*p2,g2*])*] by COMPLEX1:def 9 .=[* p1+p2, Im([*p1,g1*])+Im([*p2,g2*])*] by A1,COMPLEX1:7 .=[* p1+p2,g1+g2*] by A1,COMPLEX1:7; thus [*p1,g1*]-[*p2,g2*]=[*Re([*p1,g1*])-Re([*p2,g2*]), Im([*p1,g1*])-Im([*p2,g2*])*] by COMPLEX1:def 12 .=[* p1-p2, Im([*p1,g1*])-Im([*p2,g2*])*] by A1,COMPLEX1:7 .=[* p1-p2,g1-g2*] by A1,COMPLEX1:7; thus [*p1,g1*]*[*p2,g2*]=[* p1*p2-g1*g2, p1*g2+p2*g1 *] by A1,A2,COMPLEX1:def 10 ; thus -[*p2,g2*]=[*-Re([*p2,g2*]),-Im([*p2,g2*])*] by COMPLEX1:def 11 .=[*-p2,-Im([*p2,g2*])*] by COMPLEX1:7 .=[*-p2,-g2*] by COMPLEX1:7; thus [*p2,g2*]*' =[*Re([*p2,g2*]),-Im([*p2,g2*])*] by COMPLEX1:def 15 .=[*p2,-Im([*p2,g2*])*] by COMPLEX1:7 .=[*p2,-g2*] by COMPLEX1:7; end; theorem Th4: z ExpSeq.(n+1) = z ExpSeq.n * z /[*(n+1),0*] & z ExpSeq.0=1r & |.(z ExpSeq).n .| = (|.z.| ExpSeq ).n proof A1: now let n be Nat; thus (z ExpSeq).(n+1)=z #N (n+1) / ((n+1) !c ) by Def8 .=(z GeoSeq).(n+1) / ((n+1)!c ) by COMSEQ_3:def 2 .=(z GeoSeq).n * z /((n+1)!c ) by COMSEQ_3:def 1 .=z #N n * z / ((n+1)!c ) by COMSEQ_3:def 2 .=z #N n * z /(n!c * [*n+1,0*]) by Th1 .=(z #N n / (n!c ) )*( z / [*n+1,0*]) by XCMPLX_1:77 .=(z #N n / (n!c ) * z) / [*n+1,0*] by XCMPLX_1:75 .=z ExpSeq.n * z /[*n+1,0*] by Def8; end; A2:(z ExpSeq).0=z #N 0 /(0!c ) by Def8 .=(z GeoSeq).0 /(0!c ) by COMSEQ_3:def 2 .=1r/1r by Th1,COMSEQ_3:def 1 .=1r by COMPLEX1:85; defpred X[Nat] means |. ((z ExpSeq)).$1 .| =( |.z.| ExpSeq ).$1; ( |.z.| ExpSeq ).0 = ((|.z .|) |^ 0)/ (0!) by Def9 .= 1/(0!) by NEWTON:9 .= 1/((Prod_real_n).0) by Def7 .= 1/1 by Def5 .= 1; then A3: X[0] by A2,COMPLEX1:134; A4:now let n such that A5: X[n]; 0 < n+1 by Lm2; then A6:[*(n+1),0*] <> 0c by Th1; A7:Re([*(n+1),0*])=n+1 & Im([*(n+1),0*])=0 by COMPLEX1:7; A8: 0 <= n+1 by NAT_1:18; A9:|.[*(n+1),0*].|=abs(n+1) by A7,COMPLEX1:136 .=n+1 by A8,ABSVALUE:def 1; |. ((z ExpSeq)).(n+1) .| =|. z ExpSeq.n * z /[*(n+1),0*] .| by A1 .=|. z ExpSeq.n * z .|/|.[*(n+1),0*].| by A6,COMPLEX1:153 .=(( |.z.| ExpSeq ).n) * |.z .|/|.[*(n+1),0*].| by A5,COMPLEX1:151 .= (|.z.| |^ n)/(n!) * |.z .|/|.[*(n+1),0*].| by Def9 .=( (|.z.| |^ n) * |.z .| )/( (n!) * |.[*(n+1),0*].| ) by XCMPLX_1:84 .=( (|.z.| |^ n) * |.z .| )/( (n+1)! ) by A9,NEWTON:21 .=( (|.z.| |^ (n+1)) )/( (n+1)! ) by NEWTON:11 .=( |.z.| ExpSeq ).(n+1) by Def9; hence X[n+1]; end; for n holds X[n] from Ind(A3,A4); hence thesis by A1,A2; end; theorem Th5: 0 < k implies (Sift(seq)).k=seq.(k-'1) proof assume A1: 0 < k; then A2: 0+1 <= k by INT_1:20; consider m such that A3: m+1=k by A1,NAT_1:22; A4: m=k-1 by A3,XCMPLX_1:26; thus (Sift(seq)).k=seq.m by A3,Def12 .=seq.(k-'1) by A2,A4,SCMFSA_7:3; end; theorem Th6: Partial_Sums(seq).k=Partial_Sums(Sift(seq)).k+seq.k proof defpred X[Nat] means Partial_Sums(seq).$1=Partial_Sums(Sift(seq)).$1+seq.$1; Partial_Sums(seq).0=0c + seq.0 by COMSEQ_3:def 7 .=(Sift(seq)).0 + seq.0 by Def12 .=Partial_Sums(Sift(seq)).0+seq.0 by COMSEQ_3:def 7; then A1: X[0]; A2: for k st X[k] holds X[k+1] proof let k such that A3: Partial_Sums(seq).k=Partial_Sums(Sift(seq)).k+seq.k; thus Partial_Sums(seq).(k+1) = (Partial_Sums(Sift(seq)).k+seq.k) + seq.(k+1) by A3,COMSEQ_3:def 7 .=(Partial_Sums(Sift(seq)).k+(Sift(seq)).(k+1)) + seq.(k+1) by Def12 .=Partial_Sums(Sift(seq)).(k+1)+seq.(k+1) by COMSEQ_3:def 7; end; for k holds X[k] from Ind(A1,A2); hence thesis; end; theorem Th7: (z+w) #N n = Partial_Sums(Expan(n,z,w)).n proof A1:(z+w) #N 0 =((z+w) GeoSeq).0 by COMSEQ_3:def 2 .=1r by COMSEQ_3:def 1; A2:0-'0=0 by GOBOARD9:1; defpred X[Nat] means (z+w) #N $1 = Partial_Sums(Expan($1,z,w)).$1; Partial_Sums(Expan(0,z,w)).0 = Expan(0,z,w).0 by COMSEQ_3:def 7 .= (Coef(0)).0 * (z #N 0) * (w #N 0) by A2,Def13 .= 1r/(1r * 1r) * z #N 0 * w #N 0 by A2,Def10,Th1 .= 1r/1r * z #N 0 * w #N 0 by COMPLEX1:29 .= 1r * z #N 0 * w #N 0 by COMPLEX1:85 .= z #N 0 * w #N 0 by COMPLEX1:29 .= (z GeoSeq).0 * w #N 0 by COMSEQ_3:def 2 .= (z GeoSeq).0 * (w GeoSeq).0 by COMSEQ_3:def 2 .= 1r * (w GeoSeq).0 by COMSEQ_3:def 1 .= 1r * 1r by COMSEQ_3:def 1 .= 1r by COMPLEX1:29; then A3: X[0] by A1; A4: for n st X[n] holds X[n+1] proof let n such that A5: (z+w) #N n = Partial_Sums(Expan(n,z,w)).n; A6: (z+w) #N (n+1) =((z+w) GeoSeq ).(n+1) by COMSEQ_3:def 2 .=((z+w) GeoSeq ).n * (z+w) by COMSEQ_3:def 1 .=(Partial_Sums(Expan(n,z,w)).n) * (z+w) by A5,COMSEQ_3:def 2 .=((z+w) (#) Partial_Sums(Expan(n,z,w))).n by COMSEQ_1:def 7 .=(Partial_Sums((z+w) (#) Expan(n,z,w))).n by COMSEQ_3:29; (z+w) (#) Expan(n,z,w)=(z (#) Expan(n,z,w))+(w (#) Expan(n,z,w)) proof now let k be Nat; thus ((z+w) (#) Expan(n,z,w)).k=(z+w) * Expan(n,z,w).k by COMSEQ_1:def 7 .=z * Expan(n,z,w).k+w * Expan(n,z,w).k by XCMPLX_1:8 .=(z (#) Expan(n,z,w)).k+w * Expan(n,z,w).k by COMSEQ_1:def 7 .=(z (#) Expan(n,z,w)).k+(w (#) Expan(n,z,w)).k by COMSEQ_1:def 7 .=((z (#) Expan(n,z,w))+(w (#) Expan(n,z,w))).k by COMSEQ_1:def 4; end; hence thesis by COMSEQ_1:6; end; then A7:(z+w) #N (n+1) =( Partial_Sums(z (#) (Expan(n,z,w))) +Partial_Sums((w (#) (Expan(n,z,w))))).n by A6,COMSEQ_3:27 .= Partial_Sums((z (#) Expan(n,z,w))).n +Partial_Sums((w (#) Expan(n,z,w))).n by COMSEQ_1:def 4; A8:Partial_Sums((z (#) Expan(n,z,w))).n =Partial_Sums((z (#) Expan(n,z,w))).(n+1) proof A9: Partial_Sums((z (#) Expan(n,z,w))).(n+1) =Partial_Sums((z (#) Expan(n,z,w))).n+(z (#) Expan(n,z,w)).(n+1) by COMSEQ_3:def 7 .=Partial_Sums((z (#) Expan(n,z,w))).n +z * Expan(n,z,w).(n+1) by COMSEQ_1:def 7; n < n+1 & n+1 is Nat by REAL_1:69; then Expan(n,z,w).(n+1)=0c by Def13; hence Partial_Sums((z (#) Expan(n,z,w))).(n+1) =Partial_Sums((z (#) Expan(n,z,w))).n +0c by A9,COMPLEX1:28 .=Partial_Sums((z (#) Expan(n,z,w))).n by COMPLEX1:22; end; A10:Partial_Sums((w (#) Expan(n,z,w))).n =Partial_Sums((w (#) Expan(n,z,w))).(n+1) proof A11:Partial_Sums((w (#) Expan(n,z,w))).(n+1) =Partial_Sums((w (#) Expan(n,z,w))).n+(w (#) Expan(n,z,w)).(n+1) by COMSEQ_3:def 7 .=Partial_Sums((w (#) Expan(n,z,w))).n +w * Expan(n,z,w).(n+1) by COMSEQ_1:def 7; n < n+1 & n+1 is Nat by REAL_1:69; then Expan(n,z,w).(n+1)=0c by Def13; hence Partial_Sums((w (#) Expan(n,z,w))).(n+1) =Partial_Sums((w (#) Expan(n,z,w))).n +0c by A11,COMPLEX1:28 .=Partial_Sums((w (#) Expan(n,z,w))).n by COMPLEX1:22; end; A12:Partial_Sums((z (#) Expan(n,z,w))).(n+1) =Partial_Sums(Sift((z (#) Expan(n,z,w)))).(n+1) proof A13:Partial_Sums((z (#) Expan(n,z,w))).(n+1) =Partial_Sums(Sift((z (#) Expan(n,z,w)))).(n+1) +(z (#) Expan(n,z,w)).(n+1) by Th6; 0 +n < n+1 by REAL_1:69; then Expan(n,z,w).(n+1)=0c by Def13; then z * Expan(n,z,w).(n+1)=0c by COMPLEX1:28; hence Partial_Sums((z (#) Expan(n,z,w))).(n+1) =Partial_Sums(Sift((z (#) Expan(n,z,w)))).(n+1) +0c by A13,COMSEQ_1:def 7 .= Partial_Sums(Sift((z (#) Expan(n,z,w)))).(n+1) by COMPLEX1:22; end; A14:(w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w))) =Expan(n+1,z,w) proof now let k be Nat; A15: now assume A16: n+1 < k; A17: n < k & 1 <= k & 1 <k & 0 <k & n <k-1 & n < k-'1 proof 0 <= n by NAT_1:18; then A18: 0+1 <= n+1 by AXIOMS:24; n+1-1 < k -1 by A16,REAL_1:54; then A19: n < k-1 by XCMPLX_1:26; then A20: n+0 < k-1+1 by REAL_1:67; 1 <= k by A16,A18,AXIOMS:22; hence thesis by A16,A18,A19,A20,AXIOMS:22,SCMFSA_7:3,XCMPLX_1:27; end; ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k =(w (#) Expan(n,z,w)).k + (Sift((z (#) Expan(n,z,w)))).k by COMSEQ_1:def 4 .=(w * Expan(n,z,w).k) + (Sift((z (#) Expan(n,z,w)))).k by COMSEQ_1:def 7 .=(w * Expan(n,z,w).k) + ((z (#) Expan(n,z,w))).(k-'1) by A17,Th5 .=(w * Expan(n,z,w).k) + (z * (Expan(n,z,w).(k-'1))) by COMSEQ_1:def 7 .=(w * 0c )+ (z * ((Expan(n,z,w).(k-'1)))) by A17,Def13 .=0c + (z * 0c) by A17,Def13 .=0c + 0c by COMPLEX1:28 .=0c by COMPLEX1:22; hence ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k =Expan(n+1,z,w).k by A16,Def13; end; now assume A21: k <= (n+1); A22: now assume A23: k=n+1; thus ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k=Expan(n+1,z,w). k proof A24: n < n+1 by REAL_1:69; A25: n-'n= n-n by SCMFSA_7:3 .= 0 by XCMPLX_1:14; A26: n+1-'(n+1)= n+1-(n+1) by SCMFSA_7:3 .= 0 by XCMPLX_1:14; A27: n!c <>0c & (n+1)!c <>0c by Th1; A28: (Coef(n)).(n) = n!c /((n!c ) * (0!c )) by A25,Def10 .= n!c / (n!c ) by Th1,COMPLEX1:29 .= 1r by A27,COMPLEX1:86; A29: (Coef(n+1)).(n+1) = (n+1)!c /(((n+1)!c ) * (0!c )) by A26,Def10 .= (n+1)!c / ((n+1)!c ) by Th1,COMPLEX1:29 .= 1r by A27,COMPLEX1:86; thus ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k = (w (#) Expan(n,z,w)).(n+1)+(Sift((z (#) Expan(n,z,w)))).(n+1) by A23,COMSEQ_1:def 4 .=(w * Expan(n,z,w).(n+1)) + (Sift((z (#) Expan(n,z,w)))).(n+1) by COMSEQ_1:def 7 .=( w * 0c) + (Sift((z (#) Expan(n,z,w)))).(n+1) by A24,Def13 .= ((z (#) Expan(n,z,w))).(n) by Def12 .= z * (Expan(n,z,w)).n by COMSEQ_1:def 7 .=z * ((Coef(n)).n * (z #N n) * (w #N (n-'n))) by Def13 .=z * ((Coef(n)).n * ((z #N n) * (w #N (n-'n)))) by XCMPLX_1:4 .=(z * ((Coef(n)).n) * ((z #N n) * (w #N (n-'n)))) by XCMPLX_1:4 .= ((Coef(n)).n * z * (z #N n) * (w #N (n-'n))) by XCMPLX_1:4 .= ((Coef(n)).n * (z * (z #N n) ) * (w #N (n-'n))) by XCMPLX_1:4 .= ((Coef(n)).n * ((z GeoSeq).n * z) * (w #N (n-'n))) by COMSEQ_3:def 2 .= ((Coef(n)).n * ((z GeoSeq).(n+1)) * (w #N (n-'n))) by COMSEQ_3:def 1 .= ((Coef(n+1)).(n+1) * (z #N (n+1)) * (w #N (n-'n))) by A28,A29,COMSEQ_3:def 2 .= Expan(n+1,z,w).k by A23,A25,A26,Def13; end; end; now assume A30: k < n+1; A31: now assume A32: k=0; thus ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k =Expan(n+1,z,w).k proof A33: 0 <= n by NAT_1:18; A34: 0 <= n+1 by NAT_1:18; A35: n-'0 =n-0 by A33,SCMFSA_7:3; A36: n+1-'0 =n+1-0 by A34,SCMFSA_7:3; A37: n!c <>0c & (n+1)!c <>0c by Th1; A38: (Coef(n)).0 = n!c /((0!c ) * (n!c )) by A33,A35,Def10 .= n!c / (n!c ) by Th1,COMPLEX1:29 .= 1r by A37,COMPLEX1:86; A39: (Coef(n+1)).0 = (n+1)!c /((0!c ) * ((n+1)!c )) by A34,A36,Def10 .= (n+1)!c / ((n+1)!c ) by Th1,COMPLEX1:29 .= 1r by A37,COMPLEX1:86; thus ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k = (w (#) Expan(n,z,w)).0+(Sift((z (#) Expan(n,z,w)))).0 by A32,COMSEQ_1:def 4 .=(w * Expan(n,z,w).0) + (Sift((z (#) Expan(n,z,w)))).0 by COMSEQ_1:def 7 .=(w * Expan(n,z,w).0) + 0c by Def12 .=w * ((Coef(n)).0 * (z #N 0) * (w #N (n-'0))) by A33,Def13 .= ((Coef(n)).0 * (z #N 0) * ((w GeoSeq)).n * w) by A35,COMSEQ_3:def 2 .= (Coef(n)).0 * (z #N 0) * (((w GeoSeq)).n * w) by XCMPLX_1:4 .= ((Coef(n)).0 * (z #N 0) * ( ((w GeoSeq)).(n+1-'0)) ) by A36,COMSEQ_3:def 1 .= (Coef(n+1)).0 * (z #N 0) * (w #N (n+1-'0)) by A38,A39,COMSEQ_3:def 2 .= Expan(n+1,z,w).k by A32,A34,Def13; end; end; now assume k<>0; then A40: 0<k by NAT_1:19; then A41: 0+1 <= k by INT_1:20; k+1 <= n+1 by A30,INT_1:20; then k+1-1 <= n+1-1 by REAL_1:49; then k <= n+1-1 by XCMPLX_1:26; then A42: k <= n by XCMPLX_1:26; k < k+1 by REAL_1:69; then k-1 <= k+1-1 by REAL_1:49; then k-1 <= k by XCMPLX_1:26; then k-1 <= n by A42,AXIOMS:22; then A43: k-'1 <= n by A41,SCMFSA_7:3; thus ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k =Expan(n+1,z,w).k proof A44: ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k =(w (#) Expan(n,z,w)).k+(Sift((z (#) Expan(n,z,w)))).k by COMSEQ_1:def 4 .=(w * Expan(n,z,w).k) + (Sift((z (#) Expan(n,z,w)))).k by COMSEQ_1:def 7 .=(w * Expan(n,z,w).k) + (z (#) Expan(n,z,w)).(k-'1) by A40,Th5 .=(w * Expan(n,z,w).k) + (z * Expan(n,z,w).(k-'1)) by COMSEQ_1:def 7 .=(w * ((Coef(n)).k * (z #N k) * (w #N (n-'k)))) + (z * Expan(n,z,w).(k-'1)) by A42,Def13 .=(w * ((Coef(n)).k * (z #N k) * (w #N (n-'k)))) + (z * ((Coef(n)).(k-'1) * (z #N (k-'1)) * (w #N (n-'(k-'1))))) by A43,Def13 .=(w * ((Coef(n)).k * (z #N k)) * (w #N (n-'k))) + (z * ((Coef(n)).(k-'1) * (z #N (k-'1)) * (w #N (n-'(k-'1))))) by XCMPLX_1:4 .=(w * (Coef(n)).k * (z #N k) * (w #N (n-'k))) + (z * ((Coef(n)).(k-'1) * (z #N (k-'1)) * (w #N (n-'(k-'1))))) by XCMPLX_1:4 .=(w * (Coef(n)).k * (z #N k) * (w #N (n-'k))) + (z * ((Coef(n)).(k-'1) * (z #N (k-'1))) * (w #N (n-'(k-'1)))) by XCMPLX_1:4 .=(w * (Coef(n)).k * (z #N k) * (w #N (n-'k))) + (z * (Coef(n)).(k-'1) * (z #N (k-'1)) * (w #N (n-'(k-'1)))) by XCMPLX_1:4 .=((Coef(n)).k * (w * (z #N k)) * (w #N (n-'k) )) + (z * (Coef(n)).(k-'1) * (z #N (k-'1)) * (w #N (n-'(k-'1)))) by XCMPLX_1:4 .=((Coef(n)).k * (w * (z #N k)) * (w #N (n-'k) )) + (z * ((Coef(n)).(k-'1) * (z #N (k-'1))) * (w #N (n-'(k-'1)))) by XCMPLX_1:4 .=((Coef(n)).k * ((w * (z #N k)) * (w #N (n-'k) ))) + ( ( (Coef(n)).(k-'1) ) * ((z #N (k-'1))) * z * ( w #N (n-'(k-'1)) ) ) by XCMPLX_1:4 .=( (Coef(n)).k * ( w * (z #N k) * (w #N (n-'k)) ) + ((Coef(n)).(k-'1) * ((z #N (k-'1)) * z) * (w #N (n-'(k-'1))))) by XCMPLX_1:4 .=( (Coef(n)).k * ( w * (z #N k) * (w #N (n-'k)) ) + ( (Coef(n)).(k-'1) * ((z #N (k-'1)) * z * (w #N (n-'(k-'1)))))) by XCMPLX_1:4; A45: (w * (z #N k)) * (w #N (n-'k) ) =(z #N k) * (w #N (n+1-'k) ) proof n < n+1 by REAL_1:69; then A46: k <= n+1 by A42,AXIOMS:22; A47: (n-'k)+1=n-k+1 by A42,SCMFSA_7:3 .=n+1-k by XCMPLX_1:29 .=(n+1-'k) by A46,SCMFSA_7:3; thus (w * (z #N k)) * (w #N (n-'k) ) =((z #N k) ) * (w * (w #N (n-'k)) ) by XCMPLX_1:4 .=((z #N k) ) * ((w GeoSeq).(n-'k) * w) by COMSEQ_3:def 2 .=((z #N k) ) * ((w GeoSeq).(n+1-'k)) by A47,COMSEQ_3:def 1 .=(z #N k) * (w #N (n+1-'k)) by COMSEQ_3:def 2; end; (z #N (k-'1)) * z * (w #N (n-'(k-'1))) =(z #N k) * (w #N (n+1-'k)) proof n < n+1 by REAL_1:69; then A48: k <= n+1 by A42,AXIOMS:22; A49: (n-'(k-'1))=n-(k-'1) by A43,SCMFSA_7:3 .=n-(k-1) by A41,SCMFSA_7:3 .=n+(1-k) by XCMPLX_1:38 .=n+1-k by XCMPLX_1:29 .=(n+1-'k) by A48,SCMFSA_7:3; A50: (k-'1)+1 =k-1+1 by A41,SCMFSA_7:3 .=k by XCMPLX_1:27; (z #N (k-'1)) * z =(z GeoSeq).(k-'1) * z by COMSEQ_3:def 2 .= (z GeoSeq).k by A50,COMSEQ_3:def 1 .= z #N k by COMSEQ_3:def 2; hence (z #N (k-'1)) * z * (w #N (n-'(k-'1))) =(z #N k) * (w #N (n+1-'k)) by A49; end; then A51: ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k = ((Coef(n)).k +(Coef(n)).(k-'1) ) * ((z #N k) * (w #N (n+1-'k) )) by A44,A45,XCMPLX_1:8; A52: (Coef(n)).k +(Coef(n)).(k-'1) =n!c /( (k!c ) * ((n-'k)!c ) ) +(Coef(n)).(k-'1) by A42,Def10 .=n!c /( (k!c ) * ((n-'k)!c ) ) +n!c /(((k-'1)!c ) * (((n-'(k-'1)))!c )) by A43,Def10; A53: ( (k!c ) * ((n-'k)!c ) ) * [*(n+1-k),0*] =(k!c ) * (((n-'k)!c ) * [*(n+1-k),0*]) by XCMPLX_1:4; A54: (n-'(k-'1)) =n-(k-'1) by A43,SCMFSA_7:3 .=n-(k-1) by A41,SCMFSA_7:3 .=n+(1-k) by XCMPLX_1:38 .=n+1-k by XCMPLX_1:29 .=n+1-'k by A30,SCMFSA_7:3; A55: (((k-'1)!c ) * (((n-'(k-'1)))!c )) * [*k,0*] =[*k,0*] * ((k-'1)!c ) * (((n-'(k-'1)))!c ) by XCMPLX_1:4 .=(k!c ) * ((n+1-'k)!c ) by A40,A54,Th3; A56: (k!c ) <> 0c & (n-'k)!c <>0c & (k-'1)!c <>0c & ((n-'(k-'1)))!c <>0c & ((n+1-'k))!c <>0c & [*(n+1-k),0*] <>0c & [*k,0*] <>0c proof A57: 0 < n+1-k by A30,SQUARE_1:11; then n+1-k is Nat by INT_1:16; hence thesis by A40,A57,Th1; end; then A58: n!c /( (k!c ) * ((n-'k)!c ) ) =(n!c * [*(n+1-k),0*]) /(( (k!c ) * ((n-'k)!c ) ) * [*(n+1-k),0*]) by XCMPLX_1:92 .=(n!c * [*(n+1-k),0*])/((k!c ) * ((n+1-'k)!c )) by A42,A53,Th3; n!c /(((k-'1)!c ) * (((n-'(k-'1)))!c )) =(n!c * [*k,0*])/((k!c ) * ((n+1-'k)!c )) by A55,A56,XCMPLX_1:92; then (Coef(n)).k +(Coef(n)).(k-'1) =((n!c * [*(n+1-k),0*])+(n!c * [*k,0*])) / ((k!c ) * ((n+1-'k)!c )) by A52,A58,XCMPLX_1:63 .=( n!c * ([*(n+1-k),0*] + [*k,0*])) / ((k!c ) * ((n+1-'k)!c )) by XCMPLX_1:8 .=( n!c * [*n+1-k+k,0+0*]) / ((k!c ) * ((n+1-'k)!c )) by Lm3 .=( n!c * [*n+1,0*]) / ((k!c ) * ((n+1-'k)!c )) by XCMPLX_1:27 .=((n+1)!c ) / ((k!c ) * ((n+1-'k)!c )) by Th1 .=(Coef(n+1)).k by A30,Def10; hence ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k =(Coef(n+1)).k * (z #N k) * (w #N (n+1-'k) ) by A51,XCMPLX_1:4 .=Expan(n+1,z,w).k by A30,Def13; end; end; hence ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k =Expan(n+1,z,w).k by A31; end; hence ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k =Expan(n+1,z,w).k by A21,A22,REAL_1:def 5; end; hence ((w (#) Expan(n,z,w))+Sift((z (#) Expan(n,z,w)))).k =Expan(n+1,z,w).k by A15; end; hence thesis by COMSEQ_1:6; end; thus (z+w) #N (n+1) =(Partial_Sums((w (#) Expan(n,z,w))) + Partial_Sums(Sift((z (#) Expan(n,z,w))))).(n+1) by A7,A8,A10,A12,COMSEQ_1:def 4 .=Partial_Sums(Expan(n+1,z,w)).(n+1) by A14,COMSEQ_3:27; end; for n holds X[n] from Ind(A3,A4); hence thesis; end; theorem Th8: Expan_e(n,z,w)=(1r/(n!c )) (#) Expan(n,z,w) proof now let k be Nat; A1: now assume A2:n <k; hence Expan_e(n,z,w).k=0c by Def14 .=(1r/(n!c )) * 0c by COMPLEX1:28 .=(1r/(n!c )) * Expan(n,z,w).k by A2,Def13 .=((1r/(n!c )) (#) Expan(n,z,w)).k by COMSEQ_1:def 7; end; now assume A3:k <= n; A4:n!c <> 0c by Th1; thus A5: Expan_e(n,z,w).k = (Coef_e(n)).k * (z #N k) * (w #N (n-'k)) by A3,Def14 .= 1r/((k!c ) * ((n-'k)!c )) * (z #N k) * (w #N (n-'k)) by A3,Def11; 1r/((k!c ) * ((n-'k)!c ))=((n!c )/(n!c ))/((k!c ) * ((n-'k)!c )) by A4,COMPLEX1:86 .=(((n!c ) * 1r )/(n!c )) /((k!c ) * ((n-'k)!c)) by COMPLEX1:29 .= (1r /(n!c )) * (n!c ) /((k!c ) * ((n-'k)!c )) by XCMPLX_1:75; hence Expan_e(n,z,w).k = (1r/(n!c )) * (n!c ) /((k!c ) * ((n-'k)!c )) * ((z #N k) * (w #N (n-'k))) by A5,XCMPLX_1:4 .= (1r/(n!c )) * ( (n!c ) /((k!c ) * ((n-'k)!c )) ) * ((z #N k) * (w #N (n-'k))) by XCMPLX_1:75 .= (1r/(n!c )) * (( (n!c ) /((k!c ) * ((n-'k)!c )) ) * ((z #N k) * (w #N (n-'k)))) by XCMPLX_1:4 .= (1r/(n!c )) * ((n!c ) /((k!c ) * ((n-'k)!c )) * (z #N k) * (w #N (n-'k))) by XCMPLX_1:4 .= (1r/(n!c )) * ((Coef(n)).k * ((z #N k)) * (w #N (n-'k))) by A3,Def10 .= (1r/(n!c )) * Expan(n,z,w).k by A3,Def13 .= ( (1r/(n!c )) (#) Expan(n,z,w) ).k by COMSEQ_1:def 7; end; hence Expan_e(n,z,w).k = ( (1r/(n!c )) (#) Expan(n,z,w) ).k by A1; end; hence Expan_e(n,z,w)=((1r/(n!c )) (#) Expan(n,z,w)) by COMSEQ_1:6; end; theorem Th9: ((z+w) #N n) / (n!c) = Partial_Sums(Expan_e(n,z,w)).n proof thus ((z+w) #N n)/(n!c )= (Partial_Sums(Expan(n,z,w)).n)/(n!c) by Th7 .= ((Partial_Sums(Expan(n,z,w)).n) * 1r)/(n!c ) by COMPLEX1:29 .= (Partial_Sums(Expan(n,z,w)).n) * (1r/(n!c )) by XCMPLX_1:75 .= ((1r/(n!c )) (#) (Partial_Sums(Expan(n,z,w)))).n by COMSEQ_1:def 7 .= Partial_Sums( (1r/(n!c )) (#) Expan(n,z,w)).n by COMSEQ_3:29 .= Partial_Sums(Expan_e(n,z,w)).n by Th8; end; theorem Th10: 0c ExpSeq is absolutely_summable & Sum(0c ExpSeq)=1r proof defpred X[set] means Partial_Sums(|.0c ExpSeq.|).$1=1; Partial_Sums(|.(0c ExpSeq).|).0 =|.(0c ExpSeq).|.0 by SERIES_1:def 1 .=|. (0c ExpSeq).0 .| by COMSEQ_1:def 14 .=1 by Th4,COMPLEX1:134; then A1: X[0]; A2: for n st X[n] holds X[n+1] proof let n such that A3: Partial_Sums(|.0c ExpSeq.|).n=1; thus Partial_Sums(|.0c ExpSeq.|).(n+1) =1 + |.0c ExpSeq.|.(n+1) by A3,SERIES_1:def 1 .=1 + |.(0c ExpSeq).(n+1).| by COMSEQ_1:def 14 .=1 + |.(0c ExpSeq.n) * 0c/[*(n+1),0*] .| by Th4 .=1 by COMPLEX1:130; end; A4: 0c ExpSeq is absolutely_summable proof for n holds X[n] from Ind(A1,A2); then Partial_Sums(|.0c ExpSeq.|) is constant by SEQM_3:def 6; then Partial_Sums(|.0c ExpSeq.|) is convergent by SEQ_4:39; hence |.0c ExpSeq.| is summable by SERIES_1:def 2; end; defpred X[set] means Partial_Sums(0c ExpSeq).$1=1r; Partial_Sums(0c ExpSeq).0 =(0c ExpSeq).0 by COMSEQ_3:def 7 .=1r by Th4; then A5: X[0]; A6: for n st X[n] holds X[n+1] proof let n such that A7: Partial_Sums(0c ExpSeq).n=1r; thus Partial_Sums(0c ExpSeq).(n+1) =1r + (0c ExpSeq).(n+1) by A7,COMSEQ_3:def 7 .=1r + (0c ExpSeq.n) * 0c/[*(n+1),0*] by Th4 .=1r; end; for n holds X[n] from Ind(A5,A6); then lim(Partial_Sums(0c ExpSeq))=1r by COMSEQ_2:10; hence thesis by A4,COMSEQ_3:def 8; end; definition let z; cluster z ExpSeq -> absolutely_summable; coherence proof now assume A1:z<>0c; defpred X[set] means (z ExpSeq).$1 <> 0c; 0c <> 1r by COMPLEX1:def 7; then A2: X[0] by Th4; A3: for n st X[n] holds X[n+1] proof let n; assume A4:(z ExpSeq).n <> 0c; thus (z ExpSeq).(n+1) <> 0c proof assume A5: (z ExpSeq).(n+1) = 0c; A6: [*(n+1),0*] <>0c by COMSEQ_3:1; A7: ((z ExpSeq).n * z)/[*(n+1),0*]=0c by A5,Th4; 0c = 0c/z by COMPLEX1:87 .=(z ExpSeq).n * z/z by A6,A7,XCMPLX_1:50 .=(z ExpSeq).n * (z/z) by XCMPLX_1:75 .=(z ExpSeq).n * 1r by A1,COMPLEX1:86 .=(z ExpSeq).n by COMPLEX1:29; hence contradiction by A4; end; end; deffunc U(Nat) = |.(z ExpSeq).|.($1+1)/|.(z ExpSeq).|.$1; thus A8: for n holds X[n] from Ind(A2,A3); ex rseq st for n holds rseq.n= U(n) from ExRealSeq; then consider rseq such that A9:for n holds rseq.n=|.z ExpSeq.|.(n+1)/|.z ExpSeq.|.n; rseq is convergent & lim rseq < 1 proof now let n; A10:(z ExpSeq).n<>0c by A8; A11:[*(n+1),0*] <> 0c by COMSEQ_3:1; A12:Im([*(n+1),0*]) = 0 by COMPLEX1:7; A13:0 <= (n+1) by NAT_1:18; thus rseq.n =|.z ExpSeq.|.(n+1)/|.z ExpSeq.|.n by A9 .=|.(z ExpSeq).(n+1).|/|.z ExpSeq.|.n by COMSEQ_1:def 14 .=|.(z ExpSeq).(n+1).|/|.(z ExpSeq).n.| by COMSEQ_1:def 14 .=|.(z ExpSeq).(n+1)/(z ExpSeq).n.| by A10,COMPLEX1:153 .=|.((z ExpSeq).n * z/[*(n+1),0*]) /(z ExpSeq).n.| by Th4 .=|.((z ExpSeq).n * (z/[*(n+1),0*])) /(z ExpSeq).n.| by XCMPLX_1:75 .=|.(z/[*(n+1),0*]) .| by A10,XCMPLX_1:90 .=|.z.|/|.[*(n+1),0*] .| by A11,COMPLEX1:153 .=|.z.|/abs(Re([*(n+1),0*])) by A12,COMPLEX1:136 .=|.z.|/abs(n+1) by COMPLEX1:7 .=|.z.|/(n+1) by A13,ABSVALUE:def 1; end; then rseq is convergent & lim(rseq)=0 by SEQ_4:46; hence thesis; end; hence z ExpSeq is absolutely_summable by A8,A9,COMSEQ_3:76; end; hence thesis by Th10; end; end; theorem Th11: (z ExpSeq).0 = 1r & Expan(0,z,w).0 = 1r proof thus (z ExpSeq).0 = (z #N 0)/(0!c ) by Def8 .= (z GeoSeq).0/(0!c ) by COMSEQ_3:def 2 .= 1r/1r by Th1,COMSEQ_3:def 1 .= 1r by COMPLEX1:85; A1: 0-'0=0 by GOBOARD9:1; hence Expan(0,z,w).0 = (Coef(0)).0 * (z #N 0) * (w #N 0) by Def13 .= 1r/(1r * 1r) * z #N 0 * w #N 0 by A1,Def10,Th1 .= 1r/1r * z #N 0 * w #N 0 by COMPLEX1:29 .= 1r * z #N 0 * w #N 0 by COMPLEX1:85 .= z #N 0 * w #N 0 by COMPLEX1:29 .= (z GeoSeq).0 * w #N 0 by COMSEQ_3:def 2 .= (z GeoSeq).0 * (w GeoSeq).0 by COMSEQ_3:def 2 .= 1r * (w GeoSeq).0 by COMSEQ_3:def 1 .= 1r * 1r by COMSEQ_3:def 1 .= 1r by COMPLEX1:29; end; theorem Th12: l <= k implies (Alfa(k+1,z,w)).l = (Alfa(k,z,w)).l + Expan_e(k+1,z,w).l proof assume A1:l <= k; k < k+1 by REAL_1:69; then A2:l <= k+1 by A1,AXIOMS:22; then (k+1-'l)=k+1-l by SCMFSA_7:3; then A3: (k+1-'l)=k-l+1 by XCMPLX_1:29 .=(k-'l)+1 by A1,SCMFSA_7:3; then A4: (Alfa(k+1,z,w)).l =(z ExpSeq).l * (Partial_Sums(w ExpSeq).((k-'l)+1)) by A2,Def15 .=(z ExpSeq).l * (Partial_Sums(w ExpSeq).((k-'l)) +(w ExpSeq).((k+1-'l))) by A3,COMSEQ_3:def 7 .=((z ExpSeq).l * (Partial_Sums(w ExpSeq).((k-'l))) +((z ExpSeq).l * (w ExpSeq).((k+1-'l)))) by XCMPLX_1:8 .=(Alfa(k,z,w)).l+((z ExpSeq).l * (w ExpSeq).((k+1-'l))) by A1,Def15; (z ExpSeq).l * (w ExpSeq).((k+1-'l)) =(z #N l/(l!c )) * (w ExpSeq).((k+1-'l)) by Def8 .=(z #N l/(l!c )) * (w #N ((k+1-'l))/(((k+1-'l))!c )) by Def8 .=((z #N l) * (w #N ((k+1-'l)))/((l!c ) * (((k+1-'l))!c ))) by XCMPLX_1:77 .=(((z #N l) * (w #N ((k+1-'l))) * 1r)/((l!c ) * (((k+1-'l))!c ))) by COMPLEX1:29 .=((z #N l) * (w #N ((k+1-'l))) * ((1r/((l!c ) * (((k+1-'l))!c ))))) by XCMPLX_1:75 .= ((Coef_e(k+1)).l) * ((z #N l) * (w #N ((k+1-'l)))) by A2,Def11 .= ((Coef_e(k+1)).l) * (z #N l) * (w #N ((k+1-'l))) by XCMPLX_1:4 .=Expan_e(k+1,z,w).l by A2,Def14; hence (Alfa(k+1,z,w)).l = (Alfa(k,z,w)).l + Expan_e(k+1,z,w).l by A4; end; theorem Th13: Partial_Sums((Alfa(k+1,z,w))).k = (Partial_Sums(( Alfa(k,z,w)))).k + (Partial_Sums(( Expan_e(k+1,z,w) ))).k proof now let l be Nat; assume l <= k; hence (Alfa(k+1,z,w)).l = (Alfa(k,z,w)).l + Expan_e(k+1,z,w).l by Th12 .= ( (Alfa(k,z,w)) + Expan_e(k+1,z,w)).l by COMSEQ_1:def 4; end; hence Partial_Sums((Alfa(k+1,z,w))).k =Partial_Sums(((Alfa(k,z,w)) + Expan_e(k+1,z,w))).k by COMSEQ_3:35 .=(Partial_Sums(( Alfa(k,z,w))) +Partial_Sums(( Expan_e(k+1,z,w )))).k by COMSEQ_3:27 .= (Partial_Sums(( Alfa(k,z,w)))).k + (Partial_Sums(( Expan_e(k+1,z,w) ))).k by COMSEQ_1:def 4; end; theorem Th14: (z ExpSeq).k=(Expan_e(k,z,w)).k proof A1: 0 = k -k by XCMPLX_1:14; then A2: k-'k=0 by SCMFSA_7:3; A3: (k-'k)!c =1r by A1,Th1,SCMFSA_7:3; thus (Expan_e(k,z,w)).(k)=((Coef_e(k)).k) * (z #N k) * (w #N 0) by A2,Def14 .=( (Coef_e(k)).k) * (z #N k) * 1r by COMSEQ_3:11 .=( (Coef_e(k)).k) * (z #N k) by COMPLEX1:29 .=(1r/((k!c ) * 1r)) * (z #N k) by A3,Def11 .=(1r/((k!c ) )) * (z #N k) by COMPLEX1:29 .=((z #N k) * 1r)/(k!c ) by XCMPLX_1:75 .= (z #N k)/(k!c ) by COMPLEX1:29 .=(z ExpSeq).k by Def8; end; theorem Th15: Partial_Sums((z+w) ExpSeq).n = Partial_Sums(Alfa(n,z,w)).n proof A1:Partial_Sums((z+w) ExpSeq).0 =((z+w) ExpSeq).0 by COMSEQ_3:def 7 .=1r by Th11; defpred X[Nat] means Partial_Sums((z+w) ExpSeq).$1=Partial_Sums(Alfa($1,z,w)).$1; A2: 0-'0=0 by GOBOARD9:1; Partial_Sums(Alfa(0,z,w)).0 = Alfa(0,z,w).0 by COMSEQ_3:def 7 .= (z ExpSeq).0 * Partial_Sums(w ExpSeq).0 by A2,Def15 .= (z ExpSeq).0 * (w ExpSeq).0 by COMSEQ_3:def 7 .=1r * (w ExpSeq).0 by Th11 .=1r * 1r by Th11 .= 1r by COMPLEX1:29; then A3: X[0] by A1; A4: for k st X[k] holds X[k+1] proof let k such that A5:Partial_Sums((z+w) ExpSeq).k=Partial_Sums(Alfa(k,z,w)).k; thus Partial_Sums((z+w) ExpSeq).(k+1)=Partial_Sums(Alfa(k+1,z,w)).(k+1) proof A6: Partial_Sums((Alfa(k+1,z,w))).(k+1) =Partial_Sums((Alfa(k+1,z,w))).k+(Alfa(k+1,z,w)).(k+1) by COMSEQ_3:def 7 .=((Partial_Sums(( Alfa(k,z,w) ))).k + (Partial_Sums(( Expan_e(k+1,z,w) ))).k ) + (Alfa(k+1,z,w)).(k+1) by Th13 .= Partial_Sums((z+w) ExpSeq).k + ((Partial_Sums(( Expan_e(k+1,z,w) ))).k + (Alfa(k+1,z,w)).(k+1)) by A5,XCMPLX_1:1; k+1-'(k+1)=0 by GOBOARD9:1; then (Alfa(k+1,z,w)).(k+1) =(z ExpSeq).(k+1) * Partial_Sums(w ExpSeq).0 by Def15 .=(z ExpSeq).(k+1) * ((w ExpSeq).0) by COMSEQ_3:def 7 .=(z ExpSeq).(k+1) * 1r by Th11 .=(z ExpSeq).(k+1) by COMPLEX1:29 .=(Expan_e(k+1,z,w)).(k+1) by Th14; then (Partial_Sums(( Expan_e(k+1,z,w) ))).k + (Alfa(k+1,z,w)).(k+1) =(Partial_Sums(( Expan_e(k+1,z,w) ))).(k+1) by COMSEQ_3:def 7 .=(z+w) #N (k+1) /((k+1)!c ) by Th9; hence Partial_Sums((Alfa(k+1,z,w))).(k+1) =Partial_Sums((z+w) ExpSeq).k +(z+w) ExpSeq.(k+1) by A6,Def8 .=Partial_Sums((z+w) ExpSeq).(k+1) by COMSEQ_3:def 7; end; end; for n holds X[n] from Ind(A3,A4); hence thesis; end; theorem Th16: Partial_Sums(z ExpSeq).k * Partial_Sums(w ExpSeq).k -Partial_Sums((z+w) ExpSeq).k = Partial_Sums(Conj(k,z,w)).k proof A1: (Partial_Sums(z ExpSeq).k) * (Partial_Sums(w ExpSeq).k) -Partial_Sums((z+w) ExpSeq).k =Partial_Sums(z ExpSeq).k * Partial_Sums(w ExpSeq).k -Partial_Sums(Alfa(k,z,w)).k by Th15 .= ((Partial_Sums(w ExpSeq).k) (#) Partial_Sums(z ExpSeq)).k -Partial_Sums(Alfa(k,z,w)).k by COMSEQ_1:def 7 .=Partial_Sums((Partial_Sums(w ExpSeq).k) (#) (z ExpSeq)).k -Partial_Sums(Alfa(k,z,w)).k by COMSEQ_3:29 .=Partial_Sums((Partial_Sums(w ExpSeq).k) (#) (z ExpSeq)).k +-Partial_Sums(Alfa(k,z,w)).k by XCMPLX_0:def 8 .=Partial_Sums((Partial_Sums(w ExpSeq).k) (#) (z ExpSeq)).k +(-Partial_Sums(Alfa(k,z,w))).k by COMSEQ_1:def 9 .=(Partial_Sums((Partial_Sums(w ExpSeq).k) (#) (z ExpSeq)) +(-Partial_Sums(Alfa(k,z,w)))).k by COMSEQ_1:def 4 .=(Partial_Sums((Partial_Sums(w ExpSeq).k) (#) (z ExpSeq)) -Partial_Sums(Alfa(k,z,w))).k by COMSEQ_1:def 10 .=Partial_Sums((((Partial_Sums(w ExpSeq).k) (#) (z ExpSeq))) -(Alfa(k,z,w))).k by COMSEQ_3:28; for l be Nat st l <= k holds ((Partial_Sums(w ExpSeq).k) (#) (z ExpSeq) - (Alfa(k,z,w))).l =Conj(k,z,w).l proof let l be Nat such that A2:l <= k; thus ( ( Partial_Sums(w ExpSeq).k) (#) (z ExpSeq) - (Alfa(k,z,w)) ).l =( ( Partial_Sums(w ExpSeq).k) (#) (z ExpSeq) +-(Alfa(k,z,w)) ).l by COMSEQ_1:def 10 .=(( Partial_Sums(w ExpSeq).k) (#) (z ExpSeq)).l +(-Alfa(k,z,w)).l by COMSEQ_1:def 4 .=(( Partial_Sums(w ExpSeq).k) (#) (z ExpSeq)).l +(-Alfa(k,z,w).l) by COMSEQ_1:def 9 .=(( Partial_Sums(w ExpSeq).k) (#) (z ExpSeq)).l -Alfa(k,z,w).l by XCMPLX_0:def 8 .=(( Partial_Sums(w ExpSeq).k ) * ( (z ExpSeq).l )) -Alfa(k,z,w).l by COMSEQ_1:def 7 .=((z ExpSeq).l) * ( Partial_Sums(w ExpSeq).k) -((z ExpSeq).l) * ( Partial_Sums(w ExpSeq).(k-'l)) by A2,Def15 .=((z ExpSeq).l) * ( Partial_Sums(w ExpSeq).k -Partial_Sums(w ExpSeq).(k-'l) ) by XCMPLX_1:40 .=Conj(k,z,w).l by A2,Def17; end; hence (Partial_Sums(z ExpSeq).k) * (Partial_Sums(w ExpSeq).k) -Partial_Sums((z+w) ExpSeq).k =Partial_Sums((Conj(k,z,w))).k by A1,COMSEQ_3:35; end; theorem Th17: |. Partial_Sums((z ExpSeq)).k .| <= Partial_Sums(|.z.| ExpSeq).k & Partial_Sums((|.z.| ExpSeq)).k <= Sum(|.z.| ExpSeq) & |. Partial_Sums(( z ExpSeq)).k .| <= Sum(|.z.| ExpSeq) proof defpred X[Nat] means |. Partial_Sums(( z ExpSeq)).$1 .| <= Partial_Sums((|.z.| ExpSeq)).$1; A1: |. Partial_Sums(( z ExpSeq)).0 .| = |. ((z ExpSeq)).0 .| by COMSEQ_3:def 7 .= |. (z #N 0)/ (0 !c).| by Def8 .= |. ((z GeoSeq)).0/(0 !c) .| by COMSEQ_3:def 2 .= |. 1r /1r .| by Th1,COMSEQ_3:def 1 .= 1 by COMPLEX1:85,134; Partial_Sums((|.z.| ExpSeq)).0 = ((|.z.| ExpSeq)).0 by SERIES_1:def 1 .= ((|.z .|) |^ 0)/ (0!) by Def9 .= 1 by NEWTON:9,18; then A2: X[0] by A1; A3: for k st X[k] holds X[k+1] proof let k such that A4: |. Partial_Sums(( z ExpSeq)).k .| <= Partial_Sums((|.z.| ExpSeq)).k; A5: |. Partial_Sums(( z ExpSeq)).(k+1) .| =|. Partial_Sums(( z ExpSeq)).k + ((z ExpSeq)).(k+1) .| by COMSEQ_3:def 7; |. Partial_Sums(( z ExpSeq)).k + ((z ExpSeq)).(k+1) .| <= |. Partial_Sums(( z ExpSeq)).k.| + |. ((z ExpSeq)).(k+1) .| by COMPLEX1:142; then A6: |. Partial_Sums(( z ExpSeq)).(k+1) .| <= |. Partial_Sums(( z ExpSeq)).k.| + (|.z.| ExpSeq).(k+1) by A5,Th4; A7: |. Partial_Sums(( z ExpSeq)).k.| + (|.z.| ExpSeq).(k+1) <= Partial_Sums((|.z.| ExpSeq)).k + (|.z.| ExpSeq).(k+1) by A4,AXIOMS:24; Partial_Sums((|.z.| ExpSeq)).k + (|.z.| ExpSeq).(k+1) =Partial_Sums((|.z.| ExpSeq)).(k+1) by SERIES_1:def 1; hence |. Partial_Sums(( z ExpSeq)).(k+1) .| <= Partial_Sums((|.z.| ExpSeq)).(k+1) by A6,A7,AXIOMS:22; end; A8: for k holds X[k] from Ind(A2,A3); hence |. Partial_Sums(( z ExpSeq)).k .| <= Partial_Sums((|.z.| ExpSeq)).k; A9: Partial_Sums(|. ( z ExpSeq) .| ) is convergent by SERIES_1:def 2; A10: for k holds |. ((z ExpSeq)).k.| =(|.z.| ExpSeq).k by Th4; now let k; (|.z.| ExpSeq).k = |. ((z ExpSeq)).k.| by Th4; hence 0 <= (|.z.| ExpSeq).k by COMPLEX1:132; end; then A11:Partial_Sums((|.z.| ExpSeq )) is non-decreasing by SERIES_1:19; dom (|.z.| ExpSeq) = NAT by FUNCT_2:def 1; then A12:Partial_Sums(|.z.| ExpSeq) is bounded_above by A9,A10,COMSEQ_1:def 14; then Partial_Sums((|.z.| ExpSeq)).k <= lim(Partial_Sums((|.z.| ExpSeq ))) by A11,SEQ_4:54; hence Partial_Sums((|.z.| ExpSeq)).k <= Sum(|.z.| ExpSeq) by SERIES_1:def 3 ; A13:now let k; lim(Partial_Sums((|.z.| ExpSeq)))=Sum(|.z.| ExpSeq) by SERIES_1:def 3; hence Partial_Sums((|.z.| ExpSeq)).k <= Sum(|.z.| ExpSeq) by A11,A12,SEQ_4:54; end; A14: |. Partial_Sums(( z ExpSeq)).k .| <= Partial_Sums((|.z.| ExpSeq)).k by A8; Partial_Sums((|.z.| ExpSeq)).k <= Sum(|.z.| ExpSeq) by A13; hence |. Partial_Sums(( z ExpSeq)).k .| <= Sum(|.z.| ExpSeq) by A14,AXIOMS:22; end; theorem Th18: 1 <= Sum(|.z.| ExpSeq) proof |. Partial_Sums(z ExpSeq).0 .|=|. (z ExpSeq).0 .| by COMSEQ_3:def 7 .=1 by Th4,COMPLEX1:134; hence 1 <= Sum(|.z.| ExpSeq) by Th17; end; theorem Th19: 0 <= (|. z .| ExpSeq).n proof (|. z .| ExpSeq).n = |.((z ExpSeq)).n .| by Th4; hence 0 <= (|. z .| ExpSeq).n by COMPLEX1:132; end; theorem Th20: abs((Partial_Sums(|.z .| ExpSeq)).n) = Partial_Sums(|.z .| ExpSeq).n & (n <= m implies abs((Partial_Sums(|.z .| ExpSeq).m-Partial_Sums(|.z .| ExpSeq).n)) = Partial_Sums(|.z .| ExpSeq).m-Partial_Sums(|.z .| ExpSeq).n) proof for n holds 0 <= (|. z .| ExpSeq).n by Th19; hence thesis by COMSEQ_3:9; end; theorem Th21: abs(Partial_Sums(|.Conj(k,z,w).|).n)=Partial_Sums(|.Conj(k,z,w).|).n proof A1:now let n; |.Conj(k,z,w).|.n=|.(Conj(k,z,w)).n.| by COMSEQ_1:def 14; hence 0 <= |.Conj(k,z,w).|.n by COMPLEX1:132; end; 0 <= n by NAT_1:18; then A2:Partial_Sums(|.Conj(k,z,w).|).0 <= Partial_Sums(|.Conj(k,z,w).|).n by SEQM_3:12; A3:Partial_Sums(|.Conj(k,z,w).|).0=(|.Conj(k,z,w).|).0 by SERIES_1:def 1; 0 <= (|.Conj(k,z,w).|).0 by A1; hence thesis by A2,A3,ABSVALUE:def 1; end; theorem Th22: for p being real number st p>0 ex n st for k st n <= k holds abs(Partial_Sums(|.Conj(k,z,w).|).k) < p proof let p be real number such that A1: p>0; reconsider pp = p as Real by XREAL_0:def 1; A2: 1 <= Sum(|.z.| ExpSeq) by Th18; then A3:0 < Sum(|.z.| ExpSeq) by AXIOMS:22; A4:0 <= Sum(|.z.| ExpSeq) by A2,AXIOMS:22; 0 * Sum(|.z.| ExpSeq) < 4 * Sum(|.z.| ExpSeq) by A3,REAL_1:70; then A5: 0/(4 * Sum(|.z.| ExpSeq)) < p/(4 * Sum(|.z.| ExpSeq)) by A1,REAL_1 :73; 1 <= Sum(|.w.| ExpSeq) by Th18; then A6:0 < Sum(|.w.| ExpSeq) by AXIOMS:22; then 0 * Sum(|.w.| ExpSeq) < 4 * Sum(|.w.| ExpSeq) by REAL_1:70; then A7: 0/(4 * Sum(|.w.| ExpSeq)) < p/(4 * Sum(|.w.| ExpSeq)) by A1,REAL_1:73; set p1=min((pp/(4 * Sum(|.z.| ExpSeq))),(pp/(4 * Sum(|.w.| ExpSeq)))); A8:p1 > 0 by A5,A7,SQUARE_1:38; A9:p1>0 & p1 <= p/(4 * Sum(|.z.| ExpSeq)) & p1 <= p/(4 * Sum(|.w.| ExpSeq)) by A5,A7,SQUARE_1:35,38; A10: dom (|.z.| ExpSeq) = NAT by FUNCT_2:def 1; for n holds |. (z ExpSeq).n .| =( |.z.| ExpSeq ).n by Th4; then |. (z ExpSeq).| = |.z.| ExpSeq by A10,COMSEQ_1:def 14; then Partial_Sums(( |.z.| ExpSeq )) is convergent by SERIES_1:def 2; then consider n1 such that A11: for k,l be Nat st n1 <= k & n1 <= l holds abs(Partial_Sums(( |.z.| ExpSeq )).k - Partial_Sums(( |.z.| ExpSeq )).l) < p1 by A8,COMSEQ_3:4; consider n2 such that A12:for k,l be Nat st n2 <= k & n2 <= l holds |.Partial_Sums(( w ExpSeq )).k - Partial_Sums(( w ExpSeq )).l.| < p1 by A8,COMSEQ_3:47; set n3=n1+n2; take n4 = n3+n3; A13:now let n; let k; now let l be Nat such that A14: l <= k; thus |.Conj(k,z,w).|.l =|.( Conj(k,z,w).l) .| by COMSEQ_1:def 14 .=|.(z ExpSeq).l * (Partial_Sums(w ExpSeq).k -Partial_Sums(w ExpSeq).(k-'l)) .| by A14,Def17 .=|.(z ExpSeq).l.| * |.(Partial_Sums(w ExpSeq).k -Partial_Sums(w ExpSeq).(k-'l)).| by COMPLEX1:151 .=(|.z.| ExpSeq).l * |.(Partial_Sums(w ExpSeq).k -Partial_Sums(w ExpSeq).(k-'l)).| by Th4; end; hence for l be Nat st l <= k holds |.Conj(k,z,w).|.l =(|.z.| ExpSeq).l * |.(Partial_Sums(w ExpSeq).k -Partial_Sums(w ExpSeq).(k-'l)).|; end; A15: now let k; now let l be Nat; assume l <= k; then A16:|.Conj(k,z,w).|.l =(|.z .| ExpSeq).l * |.Partial_Sums(w ExpSeq).k -Partial_Sums(w ExpSeq).(k-'l).| by A13; A17:|.Partial_Sums(w ExpSeq).k -Partial_Sums(w ExpSeq).(k-'l).| <= |.Partial_Sums(w ExpSeq).k .| + |.Partial_Sums(w ExpSeq).(k-'l).| by COMPLEX1:143; |.Partial_Sums(w ExpSeq).k .| <= Sum(|.w.| ExpSeq) by Th17; then A18:|.Partial_Sums(w ExpSeq).k .| + |.Partial_Sums(w ExpSeq).(k-'l).| <= Sum(|.w.| ExpSeq) + |.Partial_Sums(w ExpSeq).(k-'l).| by AXIOMS:24; |.Partial_Sums(w ExpSeq).(k-'l).| <= Sum(|.w.| ExpSeq) by Th17; then A19: Sum(|.w.| ExpSeq) + |.Partial_Sums(w ExpSeq).(k-'l).| <= Sum(|.w.| ExpSeq)+ Sum(|.w.| ExpSeq) by AXIOMS:24; Sum(|.w.| ExpSeq)+ Sum(|.w.| ExpSeq)= 2 * Sum(|.w.| ExpSeq) by XCMPLX_1: 11 ; then |.Partial_Sums(w ExpSeq).k .| + |.Partial_Sums(w ExpSeq).(k-'l).| <= 2 * Sum(|.w.| ExpSeq) by A18,A19,AXIOMS:22; then A20:|.Partial_Sums(w ExpSeq).k -Partial_Sums(w ExpSeq).(k-'l).| <= 2 * Sum(|.w.| ExpSeq) by A17,AXIOMS:22; 0 <= (|.z .| ExpSeq).l by Th19; hence |.Conj(k,z,w).|.l <= (|.z .| ExpSeq).l * (2 * Sum(|.w.| ExpSeq)) by A16,A20,AXIOMS:25; end; hence for l be Nat st l <= k holds |.Conj(k,z,w).|.l <= (|.z .| ExpSeq).l * (2 * Sum(|.w.| ExpSeq)); end; now let k such that A21: n4 <= k; 0 <= n3 by NAT_1:18; then 0+n3 <= n3+n3 by AXIOMS:24; then A22:n3 <= k by A21,AXIOMS:22; 0 <= n2 by NAT_1:18; then A23: n1+0 <= n1+n2 by AXIOMS:24; then A24:n1 <= k by A22,AXIOMS:22; A25: Partial_Sums(|.Conj(k,z,w).|).k =(Partial_Sums(|.Conj(k,z,w).|).k -Partial_Sums(|.Conj(k,z,w).|).n3) +Partial_Sums(|.Conj(k,z,w).|).n3 by XCMPLX_1:27; now let l be Nat; assume A26:l <= n3; then A27:l <= k by A22,AXIOMS:22; then A28:k-'l=k-l by SCMFSA_7:3; 0 <= n1 by NAT_1:18; then A29: 0+n2 <= n1+n2 by AXIOMS:24; A30: n4-l <= k-l by A21,REAL_1:49; n3+n3-n3 <= n3+n3-l by A26,REAL_2:106; then n3 <= n3+n3-l by XCMPLX_1:26; then n3 <= k-l by A30,AXIOMS:22; then A31:n2 <= k-'l by A28,A29,AXIOMS:22; 0 <= n3 by NAT_1:18; then 0+n3 <= n3+n3 by AXIOMS:24; then n2 <= n4 by A29,AXIOMS:22; then n2 <= k by A21,AXIOMS:22; then A32: |.Partial_Sums(( w ExpSeq )).k - Partial_Sums(( w ExpSeq )).(k-'l).| < p1 by A12,A31; 0 <= (|.z .| ExpSeq).l by Th19; then (|.z .| ExpSeq).l * |.Partial_Sums(( w ExpSeq )).k - Partial_Sums(( w ExpSeq )).(k-'l).| <= (|.z .| ExpSeq).l * p1 by A32,AXIOMS:25; hence |.Conj(k,z,w).|.l <= p1 * (|.z .| ExpSeq).l by A13,A27; end; then A33:Partial_Sums(|.Conj(k,z,w).|).n3 <= Partial_Sums(|.z .| ExpSeq).n3 * p1 by COMSEQ_3:7; Partial_Sums(|.z .| ExpSeq).n3 <= Sum(|.z.| ExpSeq) by Th17; then Partial_Sums(|.z .| ExpSeq).n3 * p1 <= Sum(|.z.| ExpSeq) * p1 by A8,AXIOMS:25; then A34: Partial_Sums(|.Conj(k,z,w).|).n3 <= Sum(|.z.| ExpSeq) * p1 by A33,AXIOMS:22; A35: Sum(|.z.| ExpSeq) * p1 <= Sum(|.z.| ExpSeq) * (p/(4 * Sum (|.z.| ExpSeq))) by A4,A9,AXIOMS:25; A36: 0 <> Sum(|.z.| ExpSeq) & 4 <>0 by Th18; Sum(|.z.| ExpSeq) * (p/(4 * Sum(|.z.| ExpSeq))) =Sum(|.z.| ExpSeq) * (p * (4 * Sum(|.z.| ExpSeq))") by XCMPLX_0:def 9 .=(Sum(|.z.| ExpSeq) * p) * (4 * Sum(|.z.| ExpSeq))" by XCMPLX_1:4 .=(Sum(|.z.| ExpSeq) * p)/(4 * Sum(|.z.| ExpSeq)) by XCMPLX_0:def 9 .=p/4 by A36,XCMPLX_1:92; then A37:Partial_Sums(|.Conj(k,z,w).|).n3 <= p/4 by A34,A35,AXIOMS:22; 0 < p/4 & 0 < p/2 by A1,SEQ_2:3; then 0+p/4 < p/4 + p/4 by REAL_1:53; then p/4 < p/2 by XCMPLX_1:72; then A38: Partial_Sums(|.Conj(k,z,w).|).n3 < p/2 by A37,AXIOMS:22; k-'n3=k-n3 by A22,SCMFSA_7:3; then A39:k=(k-'n3)+n3 by XCMPLX_1:27; for l be Nat st l <= k holds |.Conj(k,z,w).|.l <= (2 * Sum(|.w.| ExpSeq)) * (|.z .| ExpSeq).l by A15; then A40:Partial_Sums(|.Conj(k,z,w).|).(k) -Partial_Sums(|.Conj(k,z,w).|).n3 <= (Partial_Sums(|.z .| ExpSeq).(k) -Partial_Sums(|.z .| ExpSeq).n3) * (2 * Sum(|.w.| ExpSeq)) by A22,A39,COMSEQ_3:8; abs((Partial_Sums(|.z .| ExpSeq).k-Partial_Sums(|.z .| ExpSeq).n3)) <= p1 by A11,A23,A24; then A41: Partial_Sums(|.z .| ExpSeq).k-Partial_Sums(|.z .| ExpSeq).n3 <= p1 by A22,Th20; A42:0 * Sum(|.w.| ExpSeq) < 2 * Sum(|.w.| ExpSeq) by A6,REAL_1:70; then (Partial_Sums(|.z .| ExpSeq).k -Partial_Sums(|.z .| ExpSeq).n3) * (2 * Sum(|.w.| ExpSeq)) <= p1 * (2 * Sum(|.w.| ExpSeq)) by A41,AXIOMS:25; then A43: Partial_Sums(|.Conj(k,z,w).|).k-Partial_Sums(|.Conj(k,z,w).|).n3 <= p1 * (2 * Sum(|.w.| ExpSeq)) by A40,AXIOMS:22; A44: (2 * Sum(|.w.| ExpSeq)) * p1 <= (2 * Sum(|.w.| ExpSeq)) * (p/(4 * Sum(|.w.| ExpSeq))) by A9,A42,AXIOMS:25; A45: 0 <> Sum(|.w.| ExpSeq) & 4 <>0 by Th18; (2 * Sum(|.w.| ExpSeq) ) * (p/(4 * Sum(|.w.| ExpSeq))) =(2 * Sum(|.w.| ExpSeq) ) * (p * (4 * Sum (|.w.| ExpSeq))") by XCMPLX_0:def 9 .=((2 * Sum(|.w.| ExpSeq) ) * p ) * (4 * Sum (|.w.| ExpSeq))" by XCMPLX_1:4 .=((2 * Sum(|.w.| ExpSeq) ) * p ) /(4 * Sum (|.w.| ExpSeq)) by XCMPLX_0:def 9 .=((2 * p ) * Sum(|.w.| ExpSeq) ) /(4 * Sum(|.w.| ExpSeq)) by XCMPLX_1: 4 .= (2 * p )/4 by A45,XCMPLX_1:92 .= (p +p )/4 by XCMPLX_1:11 .= p/2 by XCMPLX_1:73; then Partial_Sums(|.Conj(k,z,w).|).k-Partial_Sums(|.Conj(k,z,w).|).n3 <= p/2 by A43,A44,AXIOMS:22; then (Partial_Sums(|.Conj(k,z,w).|).k -Partial_Sums(|.Conj(k,z,w).|).n3) +Partial_Sums(|.Conj(k,z,w).|).n3 < (p/2)+(p/2) by A38,REAL_1:67; then Partial_Sums(|.Conj(k,z,w).|).k < p by A25,XCMPLX_1:66; hence abs(Partial_Sums(|.Conj(k,z,w).|).k) < p by Th21; end; hence for k st n4 <= k holds abs(Partial_Sums(|.Conj(k,z,w).|).k) < p; end; theorem Th23: for seq st for k holds seq.k=Partial_Sums((Conj(k,z,w))).k holds seq is convergent & lim(seq)=0c proof now let seq such that A1:for k holds seq.k=Partial_Sums((Conj(k,z,w))).k; A2: now let k; |.seq.k.|=|.Partial_Sums((Conj(k,z,w))).k.| by A1; hence |.seq.k.| <= Partial_Sums(|.Conj(k,z,w).|).k by COMSEQ_3:30; end; deffunc U(Nat) = Partial_Sums(|.Conj($1,z,w).|).$1; ex rseq be Real_Sequence st for k holds rseq.k = U(k) from ExRealSeq; then consider rseq be Real_Sequence such that A3: for k holds rseq.k=Partial_Sums(|.Conj(k,z,w).|).k; A4: now let k; |.seq.k.| <= Partial_Sums(|.Conj(k,z,w).|).k by A2; hence |.seq.k.| <= rseq.k by A3; end; rseq is convergent & lim(rseq) =0 proof A5:now let p be real number; assume p>0; then consider n such that A6:for k st n <= k holds abs(Partial_Sums(|.Conj(k,z,w).|).k) < p by Th22; take n; now let k such that A7: n <= k; abs(rseq.k-0)=abs(Partial_Sums(|.Conj(k,z,w).|).k) by A3; hence abs(rseq.k-0) < p by A6,A7; end; hence for k st n <= k holds abs(rseq.k-0) < p; end; hence rseq is convergent by SEQ_2:def 6; hence lim(rseq)=0 by A5,SEQ_2:def 7; end; hence seq is convergent & lim(seq)=0c by A4,COMSEQ_3:48; end; hence thesis; end; Lm4: Sum(z ExpSeq) * Sum(w ExpSeq) = Sum((z+w) ExpSeq) proof deffunc U(Nat) = Partial_Sums(Conj($1,z,w)).$1; ex seq st for k holds seq.k= U(k) from ExComplexSeq; then consider seq such that A1: for k holds seq.k=Partial_Sums(Conj(k,z,w)).k; now let k; thus seq.k=Partial_Sums(Conj(k,z,w)).k by A1 .=Partial_Sums(z ExpSeq).k * Partial_Sums(w ExpSeq).k -Partial_Sums((z+w) ExpSeq).k by Th16 .=(Partial_Sums(z ExpSeq) (#) Partial_Sums(w ExpSeq)).k -Partial_Sums((z+w) ExpSeq).k by COMSEQ_1:def 5 .=(Partial_Sums(z ExpSeq) (#) Partial_Sums(w ExpSeq)).k +(-Partial_Sums((z+w) ExpSeq).k) by XCMPLX_0:def 8 .=(Partial_Sums(z ExpSeq) (#) Partial_Sums(w ExpSeq)).k +(-Partial_Sums((z+w) ExpSeq)).k by COMSEQ_1:def 9 .=(Partial_Sums(z ExpSeq) (#) Partial_Sums(w ExpSeq) +(-Partial_Sums((z+w) ExpSeq))).k by COMSEQ_1:def 4 .=(Partial_Sums(z ExpSeq) (#) Partial_Sums(w ExpSeq) -Partial_Sums((z+w) ExpSeq) ).k by COMSEQ_1:def 10; end; then A2: seq=Partial_Sums(z ExpSeq) (#) Partial_Sums(w ExpSeq) -Partial_Sums((z+w) ExpSeq) by COMSEQ_1:6; A3: Partial_Sums(z ExpSeq) (#) Partial_Sums(w ExpSeq) is convergent & lim(Partial_Sums(z ExpSeq) (#) Partial_Sums(w ExpSeq)) =lim(Partial_Sums(z ExpSeq)) * lim(Partial_Sums(w ExpSeq)) by COMSEQ_2:29,30; A4: seq is convergent & lim(seq)=0c by A1,Th23; thus Sum((z+w) ExpSeq) =lim(Partial_Sums((z+w) ExpSeq)) by COMSEQ_3:def 8 .=lim(Partial_Sums(z ExpSeq)) * lim(Partial_Sums(w ExpSeq)) by A2,A3,A4,COMSEQ_3:10 .=Sum(z ExpSeq) * lim(Partial_Sums(w ExpSeq)) by COMSEQ_3:def 8 .=Sum(z ExpSeq) * Sum(w ExpSeq) by COMSEQ_3:def 8; end; begin ::Definition of Exponential Function on Complex definition func exp -> PartFunc of COMPLEX, COMPLEX means :Def18: dom it= COMPLEX & for z being Element of COMPLEX holds it.z=Sum(z ExpSeq); existence proof defpred X[set] means $1 in COMPLEX; deffunc U(Element of COMPLEX) = Sum($1 ExpSeq); consider f being PartFunc of COMPLEX, COMPLEX such that A1: for z be Element of COMPLEX holds z in dom f iff X[z] and A2: for z be Element of COMPLEX st z in dom f holds f/.z = U(z) from LambdaPFD; take f; dom(f)=COMPLEX &for z be Element of COMPLEX holds f.z = Sum(z ExpSeq) proof A3: dom(f)=COMPLEX proof A4: dom(f) c=COMPLEX by RELSET_1:12; for x be set st x in COMPLEX holds x in dom f by A1; then COMPLEX c=dom(f) by TARSKI:def 3; hence dom(f)=COMPLEX by A4,XBOOLE_0:def 10; end; for z be Element of COMPLEX holds f.z = Sum(z ExpSeq) proof let z be Element of COMPLEX; A5: z in dom f by A1; then f/.z = Sum(z ExpSeq) by A2; hence f.z = Sum(z ExpSeq) by A5,FINSEQ_4:def 4; end; hence thesis by A3; end; hence thesis; end; uniqueness proof let f1,f2 be PartFunc of COMPLEX, COMPLEX; assume A6: dom f1= COMPLEX & for z being Element of COMPLEX holds f1.z=Sum(z ExpSeq); assume A7: dom f2= COMPLEX & for z being Element of COMPLEX holds f2.z=Sum(z ExpSeq); for z being Element of COMPLEX st z in COMPLEX holds f1.z = f2.z proof let z be Element of COMPLEX such that z in COMPLEX; thus f1.z=Sum(z ExpSeq) by A6 .=f2.z by A7; end; hence f1=f2 by A6,A7,PARTFUN1:34; end; end; definition let z; func exp z -> Element of COMPLEX equals:Def19: exp.z; correctness proof exp.z=Sum(z ExpSeq) by Def18; hence exp.z is Element of COMPLEX; end; end; Lm5: for z holds exp(z)=Sum(z ExpSeq) proof let z; thus exp(z)=exp.(z) by Def19 .=Sum(z ExpSeq) by Def18; end; theorem for z1, z2 holds exp(z1+z2)=exp(z1) *exp(z2) proof let z1,z2; exp(z1+z2)= exp.(z1+z2) by Def19 .=Sum((z1+z2) ExpSeq) by Def18 .=Sum(z1 ExpSeq)*Sum(z2 ExpSeq) by Lm4 .=exp(z1)*Sum(z2 ExpSeq) by Lm5 .=exp(z1) *exp(z2) by Lm5; hence thesis; end; begin ::Definition of Sinus, Cosine, and Exponential Function on REAL definition func sin -> PartFunc of REAL, REAL means :Def20: dom it = REAL & for d being Element of REAL holds it.d=Im(Sum([*0,d*] ExpSeq)); existence proof defpred X[set] means $1 in REAL; deffunc U(Element of REAL) = Im(Sum([*0,$1*] ExpSeq)); consider f being PartFunc of REAL, REAL such that A1: for d be Element of REAL holds d in dom f iff X[d] and A2: for d be Element of REAL st d in dom f holds f/.d = U(d) from LambdaPFD; take f; dom(f)=REAL &for d be Element of REAL holds f.d = Im(Sum([*0,d*] ExpSeq)) proof A3: dom(f)=REAL proof A4: dom(f) c=REAL by RELSET_1:12; for x be set st x in REAL holds x in dom f by A1; then REAL c=dom(f) by TARSKI:def 3; hence dom(f)=REAL by A4,XBOOLE_0:def 10; end; for d be Element of REAL holds f.d = Im(Sum([*0,d*] ExpSeq)) proof let d be Element of REAL; A5: d in dom f by A1; then f/.d = Im(Sum([*0,d*] ExpSeq)) by A2; hence thesis by A5,FINSEQ_4:def 4; end; hence thesis by A3; end; hence thesis; end; uniqueness proof let f1,f2 be PartFunc of REAL, REAL; assume A6: dom f1= REAL & for d being Element of REAL holds f1.d=Im(Sum([*0,d*] ExpSeq)); assume A7: dom f2= REAL & for d being Element of REAL holds f2.d=Im(Sum([*0,d*] ExpSeq)); for d being Element of REAL st d in REAL holds f1.d = f2.d proof let d be Element of REAL such that d in REAL; thus f1.d=Im(Sum([*0,d*] ExpSeq)) by A6 .=f2.d by A7; end; hence f1=f2 by A6,A7,PARTFUN1:34; end; end; definition let th be real number; func sin th equals:Def21: sin.th; correctness; end; definition let th be real number; cluster sin th -> real; correctness proof sin th = sin.th by Def21; hence thesis; end; end; definition let th be Real; redefine func sin th -> Real; correctness by XREAL_0:def 1; end; theorem sin is Function of REAL,REAL proof sin is PartFunc of REAL,REAL & dom sin=REAL by Def20; hence thesis by FUNCT_2:130; end; reserve d for Real; definition func cos -> PartFunc of REAL, REAL means :Def22: dom it= REAL & for d holds it.d=Re(Sum([*0,d*] ExpSeq)); existence proof defpred X[set] means $1 in REAL; deffunc U(Element of REAL) = Re(Sum([*0,$1*] ExpSeq)); consider f being PartFunc of REAL, REAL such that A1: for d holds d in dom f iff X[d] and A2: for d st d in dom f holds f/.d = U(d) from LambdaPFD; take f; dom(f)=REAL &for d holds f.d = Re(Sum([*0,d*] ExpSeq)) proof A3: dom(f)=REAL proof A4: dom(f) c=REAL by RELSET_1:12; for x be set st x in REAL holds x in dom f by A1; then REAL c=dom(f) by TARSKI:def 3; hence dom(f)=REAL by A4,XBOOLE_0:def 10; end; for d holds f.d = Re(Sum([*0,d*] ExpSeq)) proof let d; A5: d in dom f by A1; then f/.d = Re(Sum([*0,d*] ExpSeq)) by A2; hence thesis by A5,FINSEQ_4:def 4; end; hence thesis by A3; end; hence thesis; end; uniqueness proof let f1,f2 be PartFunc of REAL, REAL; assume A6: dom f1= REAL & for d holds f1.d=Re(Sum([*0,d*] ExpSeq)); assume A7: dom f2= REAL & for d holds f2.d=Re(Sum([*0,d*] ExpSeq)); for d st d in REAL holds f1.d = f2.d proof let d such that d in REAL; thus f1.d=Re(Sum([*0,d*] ExpSeq)) by A6 .=f2.d by A7; end; hence f1=f2 by A6,A7,PARTFUN1:34; end; end; definition let th be real number; func cos th equals:Def23: cos.th; correctness; end; definition let th be real number; cluster cos th -> real; correctness proof cos th = cos.th by Def23; hence thesis; end; end; definition let th be Real; redefine func cos th -> Real; correctness by XREAL_0:def 1; end; theorem cos is Function of REAL,REAL proof cos is PartFunc of REAL,REAL & dom cos=REAL by Def22; hence thesis by FUNCT_2:130; end; theorem Th27: dom(sin)=REAL & dom(cos)=REAL by Def20,Def22; Lm6:Sum([*0,th*] ExpSeq )=[*cos.(th),sin.(th)*] proof A1:Im(Sum([*0,th*] ExpSeq))=sin.(th) by Def20; Re(Sum([*0,th*] ExpSeq))=cos.(th) by Def22; hence thesis by A1,COMPLEX1:8; end; theorem exp([*0,th*])=[*cos(th),sin(th)*] proof exp([*0,th*])=Sum([*0,th*] ExpSeq ) by Lm5 .=[*cos.(th),sin.(th)*] by Lm6 .=[*cos(th),sin.(th)*] by Def23 .=[*cos(th),sin(th)*] by Def21; hence thesis; end; Lm7: (Sum([*0,th*] ExpSeq))*' = Sum((-[*0,th*]) ExpSeq) proof A1: Partial_Sums(([*0,th*] ExpSeq))*' =Partial_Sums((-[*0,th*]) ExpSeq) proof A2:for n holds (([*0,th*] ExpSeq).n)*' = ((-[*0,th*]) ExpSeq).n proof defpred X[Nat] means (([*0,th*] ExpSeq).$1)*' = ((-[*0,th*]) ExpSeq).$1; (([*0,th*] ExpSeq).0)*' =1r by Th4,COMPLEX1:115 .=((-[*0,th*]) ExpSeq).0 by Th4; then A3: X[0]; A4: for n st X[n] holds X[n+1] proof let n; assume A5:(([*0,th*] ExpSeq).n)*' = ((-[*0,th*]) ExpSeq).n; thus (([*0,th*] ExpSeq).(n+1))*' =(([*0,th*] ExpSeq).n * [*0,th*]/[*(n+1),0*])*' by Th4 .=(([*0,th*] ExpSeq).n * ([*0,th*]/[*(n+1),0*]))*' by XCMPLX_1:75 .=((-[*0,th*]) ExpSeq).n * ([*0,th*]/[*(n+1),0*])*' by A5,COMPLEX1:121 .=((-[*0,th*]) ExpSeq).n * (([*0,th*])*'/([*(n+1),0*])*') by COMPLEX1:123 .=((-[*0,th*]) ExpSeq).n * ([*0,-th*] /([*(n+1),0*])*') by Lm3 .=((-[*0,th*]) ExpSeq).n * ([*0,-th*]/[*(n+1),-0*]) by Lm3 .=((-[*0,th*]) ExpSeq).n *( (-[*0, th*])/[*(n+1),0*]) by Lm3 .=((-[*0,th*]) ExpSeq).n * (-[*0, th*])/[*(n+1),0*] by XCMPLX_1:75 .=((-[*0,th*]) ExpSeq).(n+1) by Th4; end; thus for n holds X[n] from Ind(A3,A4); end; defpred X[Nat] means (Partial_Sums(([*0,th*] ExpSeq))*').$1 =Partial_Sums((-[*0,th*]) ExpSeq).$1; (Partial_Sums([*0,th*] ExpSeq)*').0 =(Partial_Sums([*0,th*] ExpSeq).0)*' by COMSEQ_2:def 2 .=(([*0,th*] ExpSeq).0)*' by COMSEQ_3:def 7 .=1r by Th4,COMPLEX1:115 .=((-[*0,th*]) ExpSeq).0 by Th4 .=Partial_Sums((-[*0,th*]) ExpSeq).0 by COMSEQ_3:def 7; then A6: X[0]; A7: for n st X[n] holds X[n+1] proof let n such that A8: (Partial_Sums(([*0,th*] ExpSeq))*').n =Partial_Sums((-[*0,th*]) ExpSeq).n; thus (Partial_Sums([*0,th*] ExpSeq)*').(n+1) =(Partial_Sums([*0,th*] ExpSeq).(n+1))*' by COMSEQ_2:def 2 .=(Partial_Sums([*0,th*] ExpSeq).n+([*0,th*] ExpSeq).(n+1))*' by COMSEQ_3:def 7 .=(Partial_Sums([*0,th*] ExpSeq).n)*'+(([*0,th*] ExpSeq).(n+1))*' by COMPLEX1:118 .=Partial_Sums((-[*0,th*]) ExpSeq).n+(([*0,th*] ExpSeq).(n+1))*' by A8,COMSEQ_2:def 2 .=Partial_Sums((-[*0,th*]) ExpSeq).n+((-[*0,th*]) ExpSeq).(n+1) by A2 .=Partial_Sums((-[*0,th*]) ExpSeq).(n+1) by COMSEQ_3:def 7; end; for n holds X[n] from Ind(A6,A7); hence thesis by COMSEQ_1:6; end; thus (Sum([*0,th*] ExpSeq))*' =(lim(Partial_Sums([*0,th*] ExpSeq)))*' by COMSEQ_3:def 8 .= lim(Partial_Sums((-[*0,th*]) ExpSeq)) by A1,COMSEQ_2:12 .= Sum((-[*0,th*]) ExpSeq) by COMSEQ_3:def 8; end; theorem (exp([*0,th*]))*'=exp(-[*0,th*]) proof (exp([*0,th*]))*'=(Sum([*0,th*] ExpSeq))*' by Lm5 .=Sum((-[*0,th*]) ExpSeq) by Lm7 .=exp(-[*0,th*]) by Lm5; hence thesis; end; Lm8: |.Sum([*0,th*] ExpSeq ).| = 1 & abs(sin.th) <= 1 & abs(cos.th) <= 1 proof A1: Sum([*0,th*] ExpSeq ) * Sum((-[*0,th*]) ExpSeq ) =Sum(([*0,th*]+(-[*0,th*])) ExpSeq ) by Lm4 .=1r by Th10,XCMPLX_0:def 6; A2: |.Sum([*0,th*] ExpSeq ).| * |.Sum([*0,th*] ExpSeq ).| =|.Sum([*0,th*] ExpSeq )*Sum([*0,th*] ExpSeq ).| by COMPLEX1:151 .=|.Sum([*0,th*] ExpSeq ) * Sum([*0,th*] ExpSeq)*'.| by COMPLEX1:155 .=1 by A1,Lm7,COMPLEX1:134; thus A3: |.Sum([*0,th*] ExpSeq ).|=1 proof A4: |.Sum([*0,th*] ExpSeq ).| =1/|.Sum([*0,th*] ExpSeq ).| by A2,XCMPLX_1:74 ; A5: |.Sum([*0,th*] ExpSeq ).| <> 0 by A2; |.Sum([*0,th*] ExpSeq ).| <> -1 by COMPLEX1:132; hence |.Sum([*0,th*] ExpSeq ).|=1 by A4,A5,XCMPLX_1:200; end; A6:abs(sin.th)=abs(Im(Sum([*0,th*] ExpSeq ))) by Def20; abs(cos.th)=abs(Re(Sum([*0,th*] ExpSeq ))) by Def22; hence thesis by A3,A6,COMSEQ_3:13; end; theorem |.exp([*0,th*]).| = 1 & abs(sin th) <= 1 & abs(cos th) <= 1 proof thus |.exp([*0,th*]).| =|.Sum([*0,th*] ExpSeq ).| by Lm5 .=1 by Lm8; abs(sin.th) <= 1 by Lm8; hence abs(sin(th)) <= 1 by Def21; abs(cos.th) <= 1 by Lm8; hence abs(cos(th)) <= 1 by Def23; end; theorem Th31: (cos.(th))^2+(sin.(th))^2=1 & (cos.(th))*(cos.(th))+(sin.(th))*(sin.(th))=1 proof A1: Sum([*0,th*] ExpSeq ) * Sum((-[*0,th*]) ExpSeq ) =Sum(([*0,th*]+(-[*0,th*])) ExpSeq ) by Lm4 .=1r by Th10,XCMPLX_0:def 6; thus A2: (cos.(th))^2+(sin.(th))^2 =(Re(Sum([*0,th*] ExpSeq )))^2+(sin.(th))^2 by Def22 .=(Re(Sum([*0,th*] ExpSeq )))^2+(Im(Sum([*0,th*] ExpSeq )))^2 by Def20 .=|.Sum([*0,th*] ExpSeq )*Sum([*0,th*] ExpSeq ).| by COMPLEX1:154 .=|.Sum([*0,th*] ExpSeq ) * Sum([*0,th*] ExpSeq)*'.| by COMPLEX1:155 .=1 by A1,Lm7,COMPLEX1:134; thus (cos.(th))*(cos.(th))+(sin.(th))*(sin.(th)) =(cos.(th))^2 +(sin.(th))*(sin.(th)) by SQUARE_1:def 3 .=1 by A2,SQUARE_1:def 3; end; theorem (cos(th))^2+(sin(th))^2=1 & (cos(th))*(cos(th))+(sin(th))*(sin(th))=1 proof thus (cos(th))^2+(sin(th))^2=(cos(th))^2+(sin.(th))^2 by Def21 .=(cos.(th))^2+(sin.(th))^2 by Def23 .=1 by Th31; thus (cos(th))*(cos(th))+(sin(th))*(sin(th))= (cos.(th))*(cos(th))+(sin(th))*(sin(th)) by Def23 .=(cos.(th))*(cos.(th))+(sin(th))*(sin(th)) by Def23 .=(cos.(th))*(cos.(th))+(sin.(th))*(sin(th)) by Def21 .=(cos.(th))*(cos.(th))+(sin.(th))*(sin.(th)) by Def21 .=1 by Th31; end; L0: 0c = [*0,0*] by ARYTM_0:def 7; theorem Th33: cos.(0)=1 & sin.(0)=0 & cos.(-th)=cos.(th) & sin.(-th)=-sin.(th) proof thus cos.(0) = 1 by Def22,Th10,COMPLEX1:15,L0; thus sin.(0) = 0 by Def20,Th10,COMPLEX1:15,L0; thus cos.(-th)=Re( Sum(([*-0,-th*]) ExpSeq) ) by Def22 .= Re( Sum((-[*0,th*]) ExpSeq) ) by Lm3 .= Re(Sum([*0,th*] ExpSeq)*') by Lm7 .= Re([*cos.(th),sin.(th)*]*') by Lm6 .= Re([*cos.(th),-sin.(th)*]) by Lm3 .= cos.(th) by COMPLEX1:7; thus sin.(-th)=Im( Sum(([*-0,-th*]) ExpSeq) ) by Def20 .= Im( Sum((-[*0,th*]) ExpSeq) ) by Lm3 .= Im(Sum([*0,th*] ExpSeq)*') by Lm7 .= Im([*cos.(th),sin.(th)*]*') by Lm6 .= Im([*cos.(th),-sin.(th)*]) by Lm3 .= -sin.(th) by COMPLEX1:7; end; theorem cos(0)=1 & sin(0)=0 & cos(-th)=cos(th) & sin(-th)=-sin(th) proof thus cos(0)=1 & sin(0)=0 by Def21,Def23,Th33; thus cos(-th)=cos.(-th) by Def23 .=cos.(th) by Th33 .=cos(th) by Def23; thus sin(-th)=sin.(-th) by Def21 .=-sin.(th) by Th33 .=-sin(th) by Def21; end; definition let th be real number; deffunc U(Nat) = (-1)|^ $1 * (th)|^ (2*$1+1)/((2*$1+1)!); func th P_sin -> Real_Sequence means :Def24: for n holds it.n= (-1)|^ n * (th)|^ (2*n+1)/((2*n+1)!); existence proof thus ex s being Real_Sequence st for n holds s.n = U(n) from ExRealSeq; end; uniqueness proof thus for s1,s2 being Real_Sequence st (for x being Nat holds s1.x = U(x)) & (for x being Nat holds s2.x = U(x)) holds s1 = s2 from FuncDefUniq; end; deffunc U(Nat) = (-1)|^ $1 * (th)|^ (2*$1)/((2*$1)!); func th P_cos -> Real_Sequence means :Def25: for n holds it.n = (-1)|^ n * (th)|^ (2*n)/((2*n)!); existence proof thus ex s being Real_Sequence st for n holds s.n = U(n) from ExRealSeq; end; uniqueness proof thus for s1,s2 being Real_Sequence st (for x being Nat holds s1.x = U(x)) & (for x being Nat holds s2.x = U(x)) holds s1 = s2 from FuncDefUniq; end; end; Lm9: for p,q,r st r<>0 holds [*p,q*]/[*r,0*]=[*p/r,q/r*]& [*p,q*]/[*0,r*]=[*q/r,-p/r*] proof let p,q,r; assume A1: r<>0; A2: Re[*p,q*]=p & Im[*p,q*]=q & Re[*r,0*]=r & Im[*r,0*]=0 & Re[*0,r*]=0 & Im[*0,r*]=r by COMPLEX1:7; then A3: [*p,q*]/[*r,0*]= [* (p* r + q* 0) / ((r)^2+ (0)^2),(r * q - p* 0)/((r)^2 +(0)^2)*] by COMPLEX1:def 14 .=[* (p* r ) / (r*r),(r * q )/((r)^2)*] by SQUARE_1:60,def 3 .=[* (p* r ) / (r*r),(r * q )/(r*r)*] by SQUARE_1:def 3 .=[* p / r,(r * q )/(r*r)*] by A1,XCMPLX_1:92 .= [* p / r, q /r *] by A1,XCMPLX_1:92; [*p,q*]/[*0,r*] =[* (p*0+q*r)/ ((0)^2+ (r)^2),(0*q - p*r) /((0)^2+ (r)^2) *] by A2,COMPLEX1:def 14 .=[* (q*r)/ ((0)^2+ (r)^2),(- p*r) /((0)^2+ (r)^2) *] by XCMPLX_1:150 .=[* (q*r)/ (r*r),(- p*r) /((r)^2) *] by SQUARE_1:60,def 3 .=[* (q*r)/ (r*r),(- p*r) /(r*r) *] by SQUARE_1:def 3 .=[* q/ r,(- p*r) /(r*r) *] by A1,XCMPLX_1:92 .=[* q/ r,((- p)*r) /(r*r) *] by XCMPLX_1:175 .=[* q/ r,(- p) /r *] by A1,XCMPLX_1:92 .=[* q/ r,- p/r *] by XCMPLX_1:188; hence thesis by A3; end; Lm10: [*p,q*]*[*r,0*]=[*p*r,q*r*]& [*p,q*]*[*0,r*]=[*-q*r,p*r*] proof A1: Re[*p,q*]=p & Im[*p,q*]=q& Re[*r,0*]=r & Im[*r,0*]=0 & Re[*0,r*]=0 & Im[*0,r*]=r by COMPLEX1:7; then A2: [*p,q*]*[*r,0*]= [*p*r-q*0, p*0+ r*q*] by COMPLEX1:def 10 .=[*p*r,q*r*]; [*p,q*]*[*0,r*]=[* p*0-q*r, p*r+ q*0*] by A1,COMPLEX1:def 10 .=[* p*0+(-q*r), p*r+ q*0*] by XCMPLX_0:def 8 .=[*-q*r,p*r*]; hence thesis by A2; end; theorem Th35: for z, k holds z#N (2*k) = (z#N k)#N 2& z#N (2*k)= (z#N 2)#N k proof let z,k; defpred X[Nat] means z#N (2*$1) = (z#N $1)#N 2 & z#N (2*$1)= (z#N 2)#N $1; A1: z#N (2*0)=1r by COMSEQ_3:11; (z#N 0)#N 2 =(1r) #N 2 by COMSEQ_3:11 .=(1r)GeoSeq.(1+1) by COMSEQ_3:def 2 .=(1r)GeoSeq.(0+1)*(1r) by COMSEQ_3:def 1 .=(1r)GeoSeq.0*(1r)*(1r) by COMSEQ_3:def 1 .= (1r)*(1r)*(1r) by COMSEQ_3:def 1 .= (1r)*(1r) by COMPLEX1:29 .= 1r by COMPLEX1:29; then A2: X[0] by A1,COMSEQ_3:11; A3: for k st X[k] holds X[k+1] proof let k; assume A4: z#N (2*k) = (z#N k)#N 2 & z#N (2*k)= (z#N 2)#N k; A5: z#N (2*(k+1))=z#N (2*k+2*1) by XCMPLX_1:8 .=z#N (2*k+(1+1)) .=z#N (2*k+1+1) by XCMPLX_1:1 .=z GeoSeq.(2*k+1+1) by COMSEQ_3:def 2 .=z GeoSeq.(2*k+1)*z by COMSEQ_3:def 1 .=z GeoSeq.(2*k)*z*z by COMSEQ_3:def 1 .=z#N (2*k)*z*z by COMSEQ_3:def 2; then A6: z#N (2*(k+1)) =((z#N k)GeoSeq.(1+1))*z*z by A4,COMSEQ_3:def 2 .=((z#N k)GeoSeq.(0+1)*(z#N k))*z*z by COMSEQ_3:def 1 .=((z#N k)GeoSeq.0*(z#N k)*(z#N k))*z*z by COMSEQ_3:def 1 .=((1r)*(z#N k)*(z#N k))*z*z by COMSEQ_3:def 1 .=(1r)*(z#N k)*((z#N k)*z)*z by XCMPLX_1:4 .=(1r)*(z#N k)*z*((z#N k)*z) by XCMPLX_1:4 .=(1r)*((z#N k)*z)*((z#N k)*z) by XCMPLX_1:4 .=(1r)*(z GeoSeq.k*z)*((z#N k)*z) by COMSEQ_3:def 2 .=(1r)*(z GeoSeq.k*z)*(z GeoSeq.k*z) by COMSEQ_3:def 2 .=(1r)*(z GeoSeq.(k+1))*(z GeoSeq.k*z) by COMSEQ_3:def 1 .=(1r)*(z GeoSeq.(k+1))*(z GeoSeq.(k+1)) by COMSEQ_3:def 1 .=(1r)*(z#N(k+1))*(z GeoSeq.(k+1)) by COMSEQ_3:def 2 .=(1r)*(z#N(k+1))*(z#N(k+1)) by COMSEQ_3:def 2 .=((z#N(k+1))GeoSeq.0)*(z#N(k+1))*(z#N(k+1)) by COMSEQ_3:def 1 .=((z#N(k+1))GeoSeq.(0+1))*(z#N(k+1)) by COMSEQ_3:def 1 .=(z#N(k+1))GeoSeq.(0+1+1) by COMSEQ_3:def 1 .=(z#N(k+1))#N 2 by COMSEQ_3:def 2; z#N (2*(k+1))=(z#N 2)#N k*(z*z) by A4,A5,XCMPLX_1:4 .= (z#N 2)#N k*(1r*z*z) by COMPLEX1:29 .= (z#N 2)#N k*(z GeoSeq.0 *z*z) by COMSEQ_3:def 1 .=(z#N 2)#N k*(z GeoSeq.(0+1) *z) by COMSEQ_3:def 1 .=(z#N 2)#N k*z GeoSeq.(0+1+1) by COMSEQ_3:def 1 .=(z#N 2)#N k*(z#N 2) by COMSEQ_3:def 2 .=(z#N 2)GeoSeq.k*(z#N 2) by COMSEQ_3:def 2 .=(z#N 2)GeoSeq.(k+1) by COMSEQ_3:def 1 .= (z#N 2)#N (k+1) by COMSEQ_3:def 2; hence thesis by A6; end; for k holds X[k] from Ind(A2,A3); hence thesis; end; L1: 1r = [*1,0*] by ARYTM_0:def 7,COMPLEX1:def 7; theorem Th36: for k, th holds [*0, th*] #N (2*k)=[*(-1)|^ k* (th |^ (2*k)),0*] & [*0, th*] #N (2*k+1)=[*0,(-1)|^ k* (th |^ (2*k+1))*] proof let k, th; A1: [*0, th*] #N (2*0)=[*0, th*] GeoSeq.0 by COMSEQ_3:def 2 .=[*1,0*] by COMSEQ_3:def 1,L1; A2: [*(-1)|^ 0* (th |^ (2*0)),0*]=[*(-1)|^ 0* th GeoSeq.0,0*] by PREPOWER:def 1 .=[*(-1)|^ 0*(1),0*] by PREPOWER:4 .=[*(-1)GeoSeq.0,0*] by PREPOWER:def 1 .=[*1,0*] by PREPOWER:4; A3: [*0, th*] #N (2*0+1)=[*0, th*] GeoSeq.(0+1) by COMSEQ_3:def 2 .=[*0, th*] GeoSeq.0*[*0,th*] by COMSEQ_3:def 1 .=[*1,0*]*[*0,th*] by COMSEQ_3:def 1,L1 .=[*-0* th,1*th*] by Lm10 .=[*0,th*]; defpred X[Nat] means [*0, th*] #N (2*$1)=[*(-1)|^ $1* (th |^ (2*$1)),0*] & [*0, th*] #N (2*$1+1)=[*0,(-1)|^ $1* (th |^ (2*$1+1))*]; [*0,(-1)|^ 0 * (th |^ (2*0+1))*]=[*0,(-1)|^ 0 * (th GeoSeq.(2*0+1))*] by PREPOWER:def 1 .= [*0,(-1)|^ 0* (th GeoSeq.0*th)*] by PREPOWER:4 .=[*0,(-1)|^ 0* (1*th)*] by PREPOWER:4 .= [*0,((-1)GeoSeq.0)* th *] by PREPOWER:def 1 .=[*0,(1)* th *] by PREPOWER:4 .=[*0,th*]; then A4: X[0] by A1,A2,A3; A5: for k st X[k] holds X[k+1] proof let k; assume A6: [*0, th*] #N (2*k)=[*(-1)|^ k* (th |^ (2*k)),0*] & [*0, th*] #N (2*k+1)=[*0,(-1)|^ k* (th |^ (2*k+1))*]; A7: [*0, th*] #N (2*(k+1))= ([*0, th*] #N 2)#N(k+1) by Th35 .=([*0, th*] #N 2) GeoSeq.(k+1) by COMSEQ_3:def 2 .=([*0, th*] #N 2) GeoSeq.k* ([*0, th*] #N 2) by COMSEQ_3:def 1 .=([*0, th*] #N 2)#N k * ([*0, th*] #N 2) by COMSEQ_3:def 2 .= [*(-1)|^ k* (th |^ (2*k)),0*]* ([*0, th*] #N 2) by A6,Th35 .= [*(-1)|^ k* (th |^ (2*k)),0*]* ([*0, th*]GeoSeq.(1+1)) by COMSEQ_3:def 2 .=[*(-1)|^ k* (th |^ (2*k)),0*]* ([*0, th*]GeoSeq.(0+1)*[*0, th*]) by COMSEQ_3:def 1 .=[*(-1)|^ k* (th |^ (2*k)),0*]* ([*0, th*]GeoSeq.0*[*0, th*] *[*0, th*]) by COMSEQ_3:def 1 .= [*(-1)|^ k* (th |^ (2*k)),0*]* (1r*[*0, th*]*[*0, th*]) by COMSEQ_3:def 1 .= [*(-1)|^ k* (th |^ (2*k)),0*]*([*0, th*]*[*0, th*]) by COMPLEX1:29 .= [*(-1)|^ k* (th |^ (2*k)),0*]* [*-th*th, 0*th*] by Lm10 .=[*(-1)|^ k* (th |^ (2*k))*(-th*th),0*(-th*th)*] by Lm10 .= [*(-1)|^ k* (th |^ (2*k))*((-1)*(th*th)),0*] by XCMPLX_1:180 .= [*(-1)|^ k* (th |^ (2*k))*(-1)*(th*th),0*] by XCMPLX_1:4 .= [*(-1)|^ k* (th |^ (2*k))*(-1)*th*th,0*] by XCMPLX_1:4 .=[*(-1)|^ k*(-1)* (th |^ (2*k))*th*th,0*] by XCMPLX_1:4 .=[*(-1)GeoSeq.k*(-1)* (th |^ (2*k))*th*th,0*] by PREPOWER:def 1 .=[*(-1)GeoSeq.(k+1)* (th |^ (2*k))*th*th,0*] by PREPOWER:4 .=[*(-1)|^(k+1)* (th |^ (2*k))*th*th,0*] by PREPOWER:def 1 .=[*(-1)|^(k+1)* (th GeoSeq.(2*k))*th*th,0*] by PREPOWER:def 1 .= [*(-1)|^(k+1)* (th GeoSeq.(2*k)*th)*th,0*] by XCMPLX_1:4 .=[*(-1)|^(k+1)* (th GeoSeq.(2*k+1))*th,0*] by PREPOWER:4 .=[*(-1)|^(k+1)* (th GeoSeq.(2*k+1)*th),0*] by XCMPLX_1:4 .=[*(-1)|^(k+1)* (th GeoSeq.(2*k+1+1)),0*] by PREPOWER:4 .=[*(-1)|^(k+1)* (th |^ (2*k+1+1)),0*] by PREPOWER:def 1 .=[*(-1)|^(k+1)* (th |^ (2*k+(1+1))),0*] by XCMPLX_1:1 .=[*(-1)|^(k+1)* (th |^ (2*k+2*1)),0*] .=[*(-1)|^(k+1)* (th |^ (2*(k+1))),0*] by XCMPLX_1:8; [*0, th*] #N (2*(k+1)+1)=[*0, th*] #N (2*k+2*1+1) by XCMPLX_1:8 .=[*0, th*] #N (2*k+(1+1)+1) .=[*0, th*] #N (2*k+1+1+1) by XCMPLX_1:1 .=[*0, th*]GeoSeq.(2*k+1+1+1) by COMSEQ_3:def 2 .=[*0, th*]GeoSeq.(2*k+1+1)*[*0, th*] by COMSEQ_3:def 1 .=[*0, th*]GeoSeq.(2*k+1)*[*0, th*]*[*0, th*] by COMSEQ_3:def 1 .=[*0, th*]GeoSeq.(2*k+1)*([*0, th*]*[*0, th*]) by XCMPLX_1:4 .=[*0, th*]GeoSeq.(2*k+1)* [*-th*th, 0*th*] by Lm10 .=[*0,(-1)|^ k* (th |^ (2*k+1))*]* [*-th*th, 0*] by A6,COMSEQ_3:def 2 .=[*0* (-th*th),(-1)|^ k* (th |^ (2*k+1))* (-th*th)*] by Lm10 .=[*0,(-1)|^ k* (th |^ (2*k+1))* ((-1)*(th*th))*] by XCMPLX_1:180 .=[*0,(-1)|^ k* (th |^ (2*k+1))*(-1)*(th*th)*] by XCMPLX_1:4 .=[*0,(-1)|^ k* (th |^ (2*k+1))*(-1)*th*th*] by XCMPLX_1:4 .=[*0,(-1)|^ k*(-1)* (th |^ (2*k+1))*th*th*] by XCMPLX_1:4 .=[*0,(-1)GeoSeq.k*(-1)* (th |^ (2*k+1))*th*th*] by PREPOWER:def 1 .=[*0,(-1)GeoSeq.(k+1)* (th |^ (2*k+1))*th*th*] by PREPOWER:4 .=[*0,(-1)|^ (k+1)* (th |^ (2*k+1))*th*th*] by PREPOWER:def 1 .=[*0,(-1)|^ (k+1)* (th GeoSeq.(2*k+1))*th*th*] by PREPOWER:def 1 .=[*0,(-1)|^ (k+1)* (th GeoSeq.(2*k+1)*th)*th*] by XCMPLX_1:4 .=[*0,(-1)|^ (k+1)* (th GeoSeq.(((2*k+1)+1)))*th*] by PREPOWER:4 .=[*0,(-1)|^ (k+1)* (th GeoSeq.((2*k+1+1))*th)*] by XCMPLX_1:4 .=[*0,(-1)|^ (k+1)* (th GeoSeq.((2*k+1+1)+1))*] by PREPOWER:4 .=[*0,(-1)|^ (k+1)* (th GeoSeq.((2*k+(1+1))+1))*] by XCMPLX_1:1 .=[*0,(-1)|^ (k+1)* (th GeoSeq.(2*k+2*1+1))*] .= [*0,(-1)|^ (k+1)* (th GeoSeq.(2*(k+1)+1))*] by XCMPLX_1:8 .=[*0,(-1)|^ (k+1)*(th |^ (2*(k+1)+1))*] by PREPOWER:def 1; hence thesis by A7; end; for k holds X[k] from Ind(A4,A5); hence thesis; end; theorem Th37: for n holds n!c=[*n!,0*] proof defpred X[Nat] means $1!c=[*$1!,0*]; A1: X[0] by Th1,NEWTON:18,ARYTM_0:def 7,COMPLEX1:def 7; A2: for k st X[k] holds X[k+1] proof let k be Nat; assume k!c=[*k!,0*]; hence (k+1)!c=[*k!,0*]*[*(k+1),0*] by Th1 .=[*k!*(k+1), 0*(k+1)*] by Lm10 .=[*(k+1)!,0*] by NEWTON:21; end; thus for k holds X[k] from Ind(A1,A2); end; theorem Th38:for th, n holds Partial_Sums(th P_sin).n = Partial_Sums(Im ([*0, th*] ExpSeq)).(2*n+1) & Partial_Sums(th P_cos).n = Partial_Sums(Re ([*0, th*] ExpSeq)).(2*n) proof let th; now A1:Partial_Sums(th P_sin).0= (th P_sin).0 by SERIES_1:def 1 .= (-1)|^ 0 * (th)|^ (2*0+1)/((2*0+1)!) by Def24; A2: (th)|^ (2*0+1)= th GeoSeq.(0+1) by PREPOWER:def 1 .= th GeoSeq.0 * th by PREPOWER:4 .= 1* th by PREPOWER:4 .= th; A3: ((2*0+1)!)= 0! * 1 by NEWTON:21 .= 1 by NEWTON:18; A4: (-1)|^ 0 = (-1) GeoSeq.0 by PREPOWER:def 1 .= 1 by PREPOWER:4; A5: Partial_Sums(th P_cos).0= (th P_cos).0 by SERIES_1:def 1 .=(-1)|^ 0 * (th)|^ (2*0)/((2*0)!) by Def25 .= 1* th GeoSeq.0 / 1 by A4,NEWTON:18,PREPOWER:def 1 .=1 by PREPOWER:4; A6: (Im ([*0, th*] ExpSeq)).0= Im (([*0, th*] ExpSeq).0) & (Im ([*0, th*] ExpSeq)).1= Im (([*0, th*] ExpSeq).1) by COMSEQ_3:def 4; A7: for q st q<>0 holds [*0, th*] /[*q,0*] =[*0,th/q*] proof let q; assume A8: q<>0; Re[*0, th*]=0 & Im[*0, th*]=th & Re[*q,0*]=q & Im[*q,0*]=0 by COMPLEX1:7; then [*0, th*] /[*q,0*] =[*(0*q+ th *0)/ (q^2 + 0^2 ), (q* th - 0 * 0)/((q)^2 + (0)^2) *] by COMPLEX1:def 14 .=[*0,(q*th)/(q*q)*] by SQUARE_1:60,def 3 .= [*0,(q/q*th)/q*] by XCMPLX_1:84 .=[*0,(1*th)/q*] by A8,XCMPLX_1:60 .=[*0, th/q*]; hence thesis; end; A9: Partial_Sums(Im ([*0, th*] ExpSeq)).(2*0+1) = Partial_Sums(Im ([*0, th*] ExpSeq)).0 + (Im ([*0, th*] ExpSeq)).1 by SERIES_1:def 1 .= (Im ([*0, th*] ExpSeq)).0+ (Im ([*0, th*] ExpSeq)).1 by SERIES_1:def 1 .= Im (1r) + Im (([*0, th*] ExpSeq).(0+1)) by A6,Th4 .=0 + Im ((([*0, th*] ExpSeq).0)* [*0, th*] /[*(0+1),0*]) by Th4,COMPLEX1:15 .= Im (1r* [*0, th*] /[*1,0*]) by Th4 .= Im([*0, th*] /[*1,0*]) by COMPLEX1:29 .=Im([*0, th/1*]) by A7 .=th by COMPLEX1:7; defpred X[Nat] means Partial_Sums(th P_sin).$1 = Partial_Sums(Im ([*0, th*] ExpSeq)).(2*$1+1) & Partial_Sums(th P_cos).$1 = Partial_Sums(Re ([*0, th*] ExpSeq)).(2*$1); Partial_Sums(Re ([*0, th*] ExpSeq)).(2*0) = (Re ([*0, th*] ExpSeq)).0 by SERIES_1:def 1 .= Re (([*0, th*] ExpSeq).0) by COMSEQ_3:def 3 .=1 by Th4,COMPLEX1:15; then A10: X[0] by A1,A2,A3,A4,A5,A9; A11: for k st X[k] holds X[k+1] proof let k be Nat; assume A12: Partial_Sums(th P_sin).k = Partial_Sums(Im ([*0, th*] ExpSeq)).(2*k+1) & Partial_Sums(th P_cos).k = Partial_Sums(Re ([*0, th*] ExpSeq)).(2*k); A13: for k holds 2*(k+1)=(2*k+1)+1 proof let k; 2*(k+1)= 2*k+2*1 by XCMPLX_1:8; then 2*(k+1)= 2*k+(1+1) .=(2*k+1)+1 by XCMPLX_1:1; hence thesis; end; A14: Partial_Sums(Im ([*0, th*] ExpSeq)).(2*(k+1)+1) = Partial_Sums(Im ([*0, th*] ExpSeq)).(2*(k+1))+ (Im ([*0, th*] ExpSeq)).(2*(k+1)+1) by SERIES_1:def 1 .= Partial_Sums(Im ([*0, th*] ExpSeq)).((2*k+1)+1) + (Im ([*0, th*] ExpSeq)).(2*(k+1)+1) by A13 .= Partial_Sums(Im ([*0, th*] ExpSeq)).(2*k+1) + (Im([*0, th*] ExpSeq)).((2*k+1)+1)+(Im ([*0, th*] ExpSeq)).(2*(k+1)+1) by SERIES_1:def 1 .= Partial_Sums(th P_sin).k + (Im([*0, th*] ExpSeq)).(2*(k+1))+(Im ([*0, th*] ExpSeq)).(2*(k+1)+1) by A12,A13 .= Partial_Sums(th P_sin).k + Im (([*0, th*] ExpSeq).(2*(k+1)))+(Im([*0, th*] ExpSeq)).(2*(k+1)+1) by COMSEQ_3:def 4 .=Partial_Sums(th P_sin).k + Im (([*0, th*] ExpSeq).(2*(k+1)))+Im(([*0, th*] ExpSeq).(2*(k+1)+1)) by COMSEQ_3:def 4 .= Partial_Sums(th P_sin).k + Im([*0, th*] #N (2*(k+1))/((2*(k+1))!c))+ Im(([*0, th*] ExpSeq).(2*(k+1)+1)) by Def8 .= Partial_Sums(th P_sin).k + Im([*0, th*] #N (2*(k+1))/((2*(k+1))!c))+ Im([*0, th*] #N (2*(k+1)+1)/((2*(k+1)+1)!c)) by Def8 .= Partial_Sums(th P_sin).k + Im( [*(-1)|^ (k+1)* (th |^ (2*(k+1))),0*]/ ((2*(k+1))!c)) +Im([*0, th*] #N (2*(k+1)+1)/((2*(k+1)+1)!c)) by Th36 .= Partial_Sums(th P_sin).k + Im( [*(-1)|^ (k+1)* (th |^ (2*(k+1))),0*]/ ((2*(k+1))!c)) + Im( [*0,(-1)|^ (k+1)* (th |^ (2*(k+1)+1))*]/((2*(k+1)+1)!c)) by Th36 .= Partial_Sums(th P_sin).k + Im( [*(-1)|^ (k+1)* (th |^ (2*(k+1))),0*]/ [*(2*(k+1))!,0*]) + Im( [*0,(-1)|^ (k+1)* (th |^ (2*(k+1)+1))*]/((2*(k+1)+1)!c)) by Th37 .= Partial_Sums(th P_sin).k + Im( [*(-1)|^ (k+1)* (th |^ (2*(k+1))),0*]/ [*(2*(k+1))!,0*]) + Im( [*0,(-1)|^ (k+1)* (th |^ (2*(k+1)+1))*]/[*(2*(k+1)+1)!,0*]) by Th37; (2*(k+1))!<>0 by NEWTON:23; then A15: Partial_Sums(Im ([*0, th*] ExpSeq)).(2*(k+1)+1) = Partial_Sums(th P_sin).k + Im( [*((-1)|^ (k+1)* (th |^ (2*(k+1))))/((2*(k+1))!),0/((2*(k+1))!)*]) + Im( [*0,(-1)|^ (k+1)* (th |^ (2*(k+1)+1))*]/[*(2*(k+1)+1)!,0*]) by A14,Lm9; (2*(k+1)+1)!<>0 by NEWTON:23; then Partial_Sums(Im ([*0, th*] ExpSeq)).(2*(k+1)+1) = Partial_Sums(th P_sin).k + Im([*((-1)|^ (k+1)* (th |^ (2*(k+1))))/((2*(k+1))!), 0/((2*(k+1))!)*])+ Im( [*0/((2*(k+1)+1)!), ((-1)|^ (k+1)* (th |^ (2*(k+1)+1)))/((2*(k+1)+1)!)*]) by A15,Lm9 .= Partial_Sums(th P_sin).k + (0/((2*(k+1))!)) + Im( [*0/((2*(k+1)+1)!), ((-1)|^ (k+1)* (th |^ (2*(k+1)+1)))/((2*(k+1)+1)!)*]) by COMPLEX1:7 .= Partial_Sums(th P_sin).k + (0/((2*(k+1))!)) + (-1)|^ (k+1)* (th |^ (2*(k+1)+1))/((2*(k+1)+1)!) by COMPLEX1:7; then A16: Partial_Sums(Im ([*0, th*] ExpSeq)).(2*(k+1)+1) = Partial_Sums(th P_sin).k + th P_sin.(k+1) by Def24 .= Partial_Sums(th P_sin).(k+1) by SERIES_1:def 1; A17: Partial_Sums(Re ([*0, th*] ExpSeq)).(2*(k+1)) =Partial_Sums(Re ([*0, th*] ExpSeq)).((2*k+1)+1) by A13 .= Partial_Sums(Re ([*0, th*] ExpSeq)).(2*k+1)+ (Re ([*0, th*] ExpSeq)).((2*k+1)+1) by SERIES_1:def 1 .=Partial_Sums(th P_cos).k + (Re ([*0, th*] ExpSeq)).(2*k+1)+ (Re ([*0, th*] ExpSeq)).((2*k+1)+1) by A12,SERIES_1:def 1 .= Partial_Sums(th P_cos).k + Re (([*0, th*] ExpSeq).(2*k+1))+ (Re ([*0, th*] ExpSeq)).((2*k+1)+1) by COMSEQ_3:def 3 .= Partial_Sums(th P_cos).k + Re (([*0, th*] ExpSeq).(2*k+1))+ Re (([*0, th*] ExpSeq).((2*k+1)+1)) by COMSEQ_3:def 3 .=Partial_Sums(th P_cos).k + Re ([*0, th*]#N (2*k+1)/ ((2*k+1)!c))+ Re (([*0, th*] ExpSeq).((2*k+1)+1)) by Def8 .= Partial_Sums(th P_cos).k + Re ([*0, th*]#N (2*k+1)/ ((2*k+1)!c))+ Re ([*0, th*]#N ((2*k+1)+1)/(((2*k+1)+1)!c)) by Def8 .= Partial_Sums(th P_cos).k + Re ([*0, th*]#N (2*k+1)/ ((2*k+1)!c))+ Re ([*0, th*]#N (2*(k+1))/(((2*k+1)+1)!c)) by A13 .= Partial_Sums(th P_cos).k + Re ([*0, th*]#N (2*k+1)/ ((2*k+1)!c))+ Re ([*0, th*]#N (2*(k+1))/((2*(k+1))!c)) by A13 .= Partial_Sums(th P_cos).k + Re ( [*0,(-1)|^ k* (th |^ (2*k+1))*]/((2*k+1)!c))+ Re ([*0, th*]#N (2*(k+1))/((2*(k+1))!c)) by Th36 .= Partial_Sums(th P_cos).k + Re ( [*0,(-1)|^ k* (th |^ (2*k+1))*]/((2*k+1)!c))+ Re ([*(-1)|^ (k+1)* (th |^ (2*(k+1))),0*]/((2*(k+1))!c)) by Th36 .= Partial_Sums(th P_cos).k + Re ( [*0,(-1)|^ k* (th |^ (2*k+1))*]/[*(2*k+1)!, 0*])+ Re ([*(-1)|^ (k+1)* (th |^ (2*(k+1))),0*]/((2*(k+1))!c)) by Th37 .= Partial_Sums(th P_cos).k + Re ( [*0,(-1)|^ k* (th |^ (2*k+1))*]/[*(2*k+1)!, 0*])+ Re ([*(-1)|^ (k+1)* (th |^ (2*(k+1))),0*]/[*(2*(k+1))!,0*]) by Th37; (2*k+1)!<>0 by NEWTON:23; then A18: Partial_Sums(Re ([*0, th*] ExpSeq)).(2*(k+1)) = Partial_Sums(th P_cos).k + Re ( [*0/((2*k+1)!),((-1)|^ k* (th |^ (2*k+1)))/((2*k+1)!)*]) + Re ([*(-1)|^ (k+1)* (th |^ (2*(k+1))),0*]/[*(2*(k+1))!,0*]) by A17,Lm9; (2*(k+1))! <>0 by NEWTON:23; then Partial_Sums(Re ([*0, th*] ExpSeq)).(2*(k+1)) = Partial_Sums(th P_cos).k + Re ( [*0/((2*k+1)!),(-1)|^ k* (th |^ (2*k+1))/((2*k+1)!)*])+ Re ([*(-1)|^ (k+1)* (th |^ (2*(k+1)))/((2*(k+1))!),0/((2*(k+1))!)*]) by A18,Lm9 .= Partial_Sums(th P_cos).k +0/((2*k+1)!)+ Re ([*(-1)|^ (k+1)* (th |^ (2*(k+1)))/((2*(k+1))!),0/((2*(k+1))!)*]) by COMPLEX1:7 .= Partial_Sums(th P_cos).k +0/((2*k+1)!)+ (-1)|^ (k+1)* (th |^ (2*(k+1)))/((2*(k+1))!) by COMPLEX1:7; then Partial_Sums(Re ([*0, th*] ExpSeq)).(2*(k+1)) = Partial_Sums(th P_cos).k + th P_cos.(k+1) by Def25 .= Partial_Sums(th P_cos).(k+1) by SERIES_1:def 1; hence thesis by A16; end; thus for n holds X[n] from Ind(A10,A11); end; hence thesis; end; theorem Th39: for th holds Partial_Sums(th P_sin) is convergent & Sum(th P_sin)=Im(Sum ([*0,th*] ExpSeq)) &Partial_Sums(th P_cos) is convergent & Sum(th P_cos)=Re(Sum ([*0,th*] ExpSeq)) proof let th; Re ([*0,th*] ExpSeq) is summable & Im ([*0,th*] ExpSeq) is summable & Sum(([*0,th*] ExpSeq))=[*Sum(Re ([*0,th*] ExpSeq)),Sum (Im ([*0,th*] ExpSeq))*] by COMSEQ_3:54; then Sum(Re ([*0,th*] ExpSeq))= Re (Sum(([*0,th*] ExpSeq)))& Sum(Im ([*0,th*] ExpSeq))=Im (Sum(([*0,th*] ExpSeq))) by COMPLEX1:7; then A1: Partial_Sums(Re ([*0,th*] ExpSeq)) is convergent & lim Partial_Sums(Re ([*0,th*] ExpSeq))= Re (Sum(([*0,th*] ExpSeq)))& Partial_Sums(Im ([*0,th*] ExpSeq)) is convergent & lim Partial_Sums(Im ([*0,th*] ExpSeq))=Im (Sum(([*0,th*] ExpSeq))) by SERIES_1:def 2,def 3; A2: now let p be real number; assume p>0; then consider n such that A3:for k st n <= k holds abs(Partial_Sums(Re ([*0,th*] ExpSeq)).k- Re (Sum(([*0,th*] ExpSeq)))) < p by A1,SEQ_2:def 7; take n; now let k such that A4: n <= k; A5: abs(Partial_Sums(th P_cos).k-Re (Sum(([*0,th*] ExpSeq)))) =abs(Partial_Sums(Re ([*0,th*] ExpSeq)).(2*k)- Re (Sum(([*0,th*] ExpSeq)))) by Th38; 2*k=k+k by XCMPLX_1:11; then n <= 2*k by A4,NAT_1:37; hence abs(Partial_Sums(th P_cos).k-Re (Sum(([*0,th*] ExpSeq)))) < p by A3,A5; end; hence for k st n <= k holds abs(Partial_Sums(th P_cos).k-Re (Sum(([*0,th*] ExpSeq)))) < p; end; then Partial_Sums(th P_cos) is convergent by SEQ_2:def 6; then A6: lim(Partial_Sums(th P_cos))=Re(Sum ([*0,th*] ExpSeq)) by A2,SEQ_2:def 7; A7: now let p be real number; assume p>0; then consider n such that A8:for k st n <= k holds abs(Partial_Sums(Im ([*0,th*] ExpSeq)).k- Im (Sum(([*0,th*] ExpSeq)))) < p by A1,SEQ_2:def 7; take n; now let k such that A9: n <= k; A10: abs(Partial_Sums(th P_sin).k-Im (Sum(([*0,th*] ExpSeq)))) =abs(Partial_Sums(Im ([*0,th*] ExpSeq)).(2*k+1)- Im (Sum(([*0,th*] ExpSeq)))) by Th38; 2*k=k+k by XCMPLX_1:11; then n <= 2*k by A9,NAT_1:37; then n<2*k+1 by NAT_1:38; hence abs(Partial_Sums(th P_sin).k-Im (Sum(([*0,th*] ExpSeq)))) < p by A8,A10; end; hence for k st n <= k holds abs(Partial_Sums(th P_sin).k-Im (Sum(([*0,th*] ExpSeq)))) < p; end; then Partial_Sums(th P_sin) is convergent by SEQ_2:def 6; then lim(Partial_Sums(th P_sin))=Im(Sum ([*0,th*] ExpSeq)) by A7,SEQ_2:def 7; hence thesis by A2,A6,A7,SEQ_2:def 6,SERIES_1:def 3; end; theorem Th40: for th holds cos.th=Sum(th P_cos) & sin.th=Sum(th P_sin) proof let th; A1: sin.th = Im(Sum([*0,th*] ExpSeq)) by Def20; cos.th=Re(Sum([*0,th*] ExpSeq)) by Def22; hence thesis by A1,Th39; end; theorem Th41: for p,th,rseq st rseq is convergent& lim(rseq)=th &(for n holds rseq.n >= p) holds th >= p proof let p,th, rseq such that A1: rseq is convergent & lim(rseq)=th &(for n holds rseq.n >= p); deffunc U(Nat) = p; consider rseq1 such that A2: for n holds rseq1.n= U(n) from ExRealSeq; A3:rseq1 is constant by A2,SEQM_3:def 6; then A4: lim(rseq1)=rseq1.0 by SEQ_4:41 .=p by A2; A5: rseq1 is convergent by A3,SEQ_4:39; now let n; rseq.n >= p by A1; hence rseq.n >= rseq1.n by A2; end; hence thesis by A1,A4,A5,SEQ_2:32; end; deffunc U(Real) = 2*$1+1; consider bq being Real_Sequence such that Lm11: for n holds bq.n= U(n) from ExRealSeq; bq is increasing Seq_of_Nat proof A1:bq is increasing proof for n,k st n<k holds bq.n<bq.k proof let n,k; assume n<k; then 2*n<2*k by REAL_1:70; then 2*n+1<2*k+1 by REAL_1:53; then bq.n<2*k+1 by Lm11; hence thesis by Lm11; end; hence thesis by SEQM_3:7; end; for n holds bq.n is Nat proof let n; 2*n+1 is Nat; hence thesis by Lm11; end; hence thesis by A1,SEQM_3:29; end; then reconsider bq as increasing Seq_of_Nat; Lm12: for th,th1,th2,th3 be real number holds th |^ 0=1 & th |^ (2*n)=(th |^ n)|^ 2 & th |^ 1=th & th |^ 2=th * th & (-1)|^(2*n)=1 &(-1)|^ (2*n+1)=-1 proof let th,th1,th2,th3 be real number; thus th |^ 0=th GeoSeq.0 by PREPOWER:def 1 .=1 by PREPOWER:4; thus th |^ (2*n)=(th |^ n)|^ 2 by NEWTON:14; thus A1: th |^ 1=th GeoSeq.(0+1)by PREPOWER:def 1 .=th GeoSeq.0 * th by PREPOWER:4 .=1* th by PREPOWER:4 .=th; thus th |^ 2=th |^ (1+1) .= th*th by A1,NEWTON:13; thus A2: (-1)|^(2*n)=(1)|^(2*n) by POWER:1 .=1 by NEWTON:15; thus (-1)|^ (2*n+1)=(-1)|^ (2*n)*(-1) by NEWTON:11 .=-1 by A2; end; Lm13: [*th,th1*]+[*th2,th3*]=[*th+th2,th1+th3*] &(5/6)^2=25/36 &(th>0 & th1>0 implies th+th1>0) proof thus [*th,th1*]+[*th2,th3*]=[*th+th2,th1+th3*] proof Re[*th,th1*]=th&Im[*th,th1*]=th1&Re[*th2,th3*]=th2 &Im[*th2,th3*]=th3 by COMPLEX1:7; hence thesis by COMPLEX1:def 9; end; thus (5/6)^2=(5/6)*(5/6) by SQUARE_1:def 3 .=25/36; th>0 implies th1+th>th1 by REAL_1:69; hence (th>0 & th1>0 implies th+th1>0) by AXIOMS:22; end; theorem Th42: for n,k,m st n < k holds m!>0 & n!<=k! proof let n,k,m; assume A1: n < k; A2: for m holds 1<= m+1 proof let m; 0 <= m by NAT_1:18; then 0+1<= m+1 by AXIOMS:24; hence 1<= m+1; end; deffunc U(Nat) = $1!; consider rseq such that A3:for l holds rseq.l=U(l) from ExRealSeq; A4: rseq is non-decreasing proof for l holds rseq.l<=rseq.(l+1)& rseq.l>0 proof let l; defpred X[Nat] means rseq.$1<=rseq.($1+1)& rseq.$1>0; A5: rseq.(0+1)=(0+1)! by A3 .=0!*1 by NEWTON:21 .=1 by NEWTON:18; rseq.0=1 by A3,NEWTON:18; then A6: X[0] by A5; A7: for l st X[l] holds X[l+1] proof let l; assume rseq.l<=rseq.(l+1)& rseq.l>0; then A8: rseq.(l+1)>0; A9: rseq.(l+1+1)= (l+1+1)! by A3 .=(l+1)!*(l+1+1) by NEWTON:21 .=rseq.(l+1) *(l+1+1) by A3; (l+1+1)>=1 by A2; hence thesis by A8,A9,REAL_2:146; end; for l holds X[l] from Ind(A6,A7); hence thesis; end; hence thesis by SEQM_3:def 13; end; then rseq.0 <= rseq.m by SEQM_3:21; then rseq.0 <= m! by A3; then A10: m!>=1 by A3,NEWTON:18; n!=rseq.n & k! =rseq.k by A3; hence thesis by A1,A4,A10,AXIOMS:22,SEQM_3:12; end; theorem Th43: for th,n,k st 0<=th & th <=1 & n<=k holds th |^ k <= th |^ n proof let th,n,k; assume A1: 0<=th & th <=1& n<=k; A2: th GeoSeq is non-increasing proof for m holds th GeoSeq.(m+1)<=th GeoSeq.m& th GeoSeq.m >=0 proof let m; defpred X[Nat] means th GeoSeq.($1+1)<=th GeoSeq.$1 &th GeoSeq.$1 >=0; th GeoSeq.(0+1)=th GeoSeq.0 * th by PREPOWER:4 .= 1*th by PREPOWER:4 .=th; then A3: X[0] by A1,PREPOWER:4; A4: for m st X[m] holds X[m+1] proof let m; assume A5: th GeoSeq.(m+1)<=th GeoSeq.m &th GeoSeq.m >=0; A6: th GeoSeq.(m+1+1)=th GeoSeq.(m+1)*th by PREPOWER:4; th GeoSeq.(m+1)=th GeoSeq.(m)*th by PREPOWER:4; then th GeoSeq.(m+1)>=0 by A1,A5,REAL_2:121; hence thesis by A1,A6,REAL_2:147; end; for m holds X[m] from Ind(A3,A4); hence thesis; end; hence thesis by SEQM_3:def 14; end; A7: th |^ k=th GeoSeq. k by PREPOWER:def 1; th |^ n=th GeoSeq. n by PREPOWER:def 1; hence thesis by A1,A2,A7,SEQM_3:14; end; theorem Th44: for th,n holds [*th,0*]#N n=[* th |^ n,0 *] proof let th, n; defpred X[Nat] means [*th,0*]#N $1 =[* th |^ $1,0 *]; [*th,0*]#N 0=[* 1,0 *] by COMSEQ_3:11,L1 .=[* th |^ 0,0 *] by Lm12; then A1: X[0]; A2: for k st X[k] holds X[k+1] proof let k; assume A3: [*th,0*]#N k =[* th |^ k,0 *]; [*th,0*]#N (k+1)=[*th,0*] GeoSeq.(k+1) by COMSEQ_3:def 2 .=[*th,0*] GeoSeq.k * [*th,0*] by COMSEQ_3:def 1 .=[* th |^ k,0 *]* [*th,0*] by A3,COMSEQ_3:def 2 .=[* th |^ k*th,0*th *] by Lm10 .=[* th |^ (k+1),0 *] by NEWTON:11; hence thesis; end; for n holds X[n] from Ind(A1,A2); hence thesis; end; theorem Th45: for th, n holds [*th,0*] #N n /(n!c )=[*(th|^ n) /(n!),0*] proof let th, n; A1: [*th,0*] #N n /(n!c )=[* th |^ n,0 *]/(n!c ) by Th44 .=[* th |^ n,0 *]/[*n!,0*] by Th37; n!<>0 by NEWTON:23; then [*th,0*] #N n /(n!c )=[*(th|^ n) /(n!),0/(n!)*] by A1,Lm9; hence thesis; end; theorem Th46: Im(Sum([*p,0*] ExpSeq))=0 proof A1: for n holds (Partial_Sums(Im([*p,0*] ExpSeq))).n=0 proof let n; defpred X[Nat] means (Partial_Sums(Im([*p,0*] ExpSeq))).$1=0; (Partial_Sums(Im([*p,0*] ExpSeq))).0=Im([*p,0*] ExpSeq).0 by SERIES_1:def 1 .=Im([*p,0*] ExpSeq.0 ) by COMSEQ_3:def 4 .=0 by Th4,COMPLEX1:15; then A2: X[0]; A3: for k st X[k] holds X[k+1] proof let k; assume (Partial_Sums(Im([*p,0*] ExpSeq))).k=0; then (Partial_Sums(Im([*p,0*] ExpSeq))).(k+1) =0+ (Im([*p,0*] ExpSeq)).(k+1) by SERIES_1:def 1 .=Im(([*p,0*] ExpSeq).(k+1)) by COMSEQ_3:def 4 .=Im([*p,0*] #N (k+1) /((k+1)!c) ) by Def8 .=Im[*(p|^ (k+1))/((k+1)!),0*] by Th45 .=0 by COMPLEX1:7; hence thesis; end; for n holds X[n] from Ind(A2,A3); hence thesis; end; for n,m holds (Partial_Sums(Im([*p,0*] ExpSeq))).n= (Partial_Sums(Im([*p,0*] ExpSeq))).m proof let n,m; (Partial_Sums(Im([*p,0*] ExpSeq))).n=0& (Partial_Sums(Im([*p,0*] ExpSeq))).m=0 by A1; hence thesis; end; then (Partial_Sums(Im([*p,0*] ExpSeq))) is constant by SEQM_3:18; then A4: lim Partial_Sums(Im([*p,0*] ExpSeq))=Partial_Sums(Im([*p,0*] ExpSeq)).0 by SEQ_4:41 .= 0 by A1; Im(Sum([*p,0*] ExpSeq))=Im[*Sum(Re ([*p,0*] ExpSeq)),Sum (Im ([*p,0*] ExpSeq))*] by COMSEQ_3:54 .= Sum(Im ([*p,0*] ExpSeq )) by COMPLEX1:7; hence thesis by A4,SERIES_1:def 3; end; theorem Th47: cos.1>0 & sin.1>0 & cos.1<sin.1 proof A1: cos.1>=1/2 proof A2: (Partial_Sums(1 P_cos))*bq is_subsequence_of Partial_Sums(1 P_cos) by SEQM_3:def 10; A3: Partial_Sums(1 P_cos) is convergent & cos.1=Sum(1 P_cos) by Th39,Th40; then A4: (Partial_Sums(1 P_cos))*bq is convergent by A2,SEQ_4:29; lim ((Partial_Sums(1 P_cos))*bq )=lim(Partial_Sums(1 P_cos)) by A2,A3, SEQ_4:30; then A5: lim ((Partial_Sums(1 P_cos))*bq )= cos.1 by A3,SERIES_1:def 3; for n holds ((Partial_Sums(1 P_cos))*bq).n >=1/2 proof let n; defpred X[Nat] means ((Partial_Sums(1 P_cos))*bq).$1 >= 1/2; ((Partial_Sums(1 P_cos))*bq).0=(Partial_Sums(1 P_cos)).(bq.0) by SEQM_3:31 .= (Partial_Sums(1 P_cos)).(2*0+1) by Lm11 .=(Partial_Sums(1 P_cos)).0+(1 P_cos).(0+1) by SERIES_1:def 1 .= (1 P_cos).0 +(1 P_cos).(0+1) by SERIES_1:def 1 .=(-1)|^ 0 * (1)|^ (2*0)/((2*0)!)+(1 P_cos).(1) by Def25 .= (-1)|^ 0 * (1)|^ (2*0)/((2*0)!)+ (-1)|^ 1 * (1)|^ (2*1)/((2*1)!) by Def25 .=1* (1)|^ (2*0)/((2*0)!)+ (-1)|^ 1 * (1)|^ (2*1)/((2*1)!) by Lm12 .=1/1 + (-1)|^ 1 * (1)|^ (2*1)/((2*1)!) by Lm12,NEWTON:18 .=1+ (-1)* (1)|^ (2*1)/((2*1)!) by Lm12 .=1+ (-1)*1/((2*1)!) by NEWTON:15 .=1+(-1)/(1! * (1+1)) by NEWTON:21 .=1+(-1)/(0! * (0+1) *2) by NEWTON:21 .=1/2 by NEWTON:18; then A6: X[0]; A7: for k st X[k] holds X[k+1] proof let k; assume A8: ((Partial_Sums(1 P_cos))*bq).k >= 1/2; ((Partial_Sums(1 P_cos))*bq).(k+1) =(Partial_Sums(1 P_cos)).(bq.(k+1)) by SEQM_3:31 .=(Partial_Sums(1 P_cos)).(2*(k+1)+1) by Lm11 .=(Partial_Sums(1 P_cos)).(2*(k+1)) +(1 P_cos).(2*(k+1)+1) by SERIES_1:def 1 .= (Partial_Sums(1 P_cos)).(2*k+2*1) +(1 P_cos).(2*(k+1)+1) by XCMPLX_1:8 .= (Partial_Sums(1 P_cos)).(2*k+(1+1))+(1 P_cos).(2*(k+1)+1) .=(Partial_Sums(1 P_cos)).(2*k+1+1)+(1 P_cos).(2*(k+1)+1) by XCMPLX_1:1 .=(Partial_Sums(1 P_cos)).(2*k+1) + (1 P_cos).(2*k+1+1)+ (1 P_cos).(2*(k+1)+1) by SERIES_1:def 1 .= (Partial_Sums(1 P_cos)).(bq.k)+ (1 P_cos).(2*k+1+1)+ (1 P_cos).(2*(k+1)+1) by Lm11 .=((Partial_Sums(1 P_cos))*bq).k+ (1 P_cos).(2*k+1+1)+ (1 P_cos).(2*(k+1)+1) by SEQM_3:31; then A9: ((Partial_Sums(1 P_cos))*bq).(k+1)-((Partial_Sums(1 P_cos))*bq).k = ((Partial_Sums(1 P_cos))*bq).k+((1 P_cos).(2*k+1+1) + (1 P_cos).(2*(k+1)+1))-((Partial_Sums(1 P_cos))*bq).k by XCMPLX_1:1 .=((Partial_Sums(1 P_cos))*bq).k-((Partial_Sums(1 P_cos))*bq).k +((1 P_cos).(2*k+1+1)+ (1 P_cos).(2*(k+1)+1)) by XCMPLX_1:29 .=0+((1 P_cos).(2*k+1+1)+ (1 P_cos).(2*(k+1)+1)) by XCMPLX_1:14 .=(1 P_cos).(2*k+1+1)+ (1 P_cos).(2*(k+1)+1); A10: (1 P_cos).(2*k+1+1)=(1 P_cos).(2*k+(1+1)) by XCMPLX_1:1 .=(1 P_cos).(2*k+2*1) .=(1 P_cos).(2*(k+1)) by XCMPLX_1:8 .=(-1)|^ (2*(k+1)) * (1)|^ (2*(2*(k+1)))/((2*(2*(k+1)))!) by Def25 .=(1)* (1)|^ (2*(2*(k+1)))/((2*(2*(k+1)))!) by Lm12 .=1/((2*(2*(k+1)))!) by NEWTON:15; (1 P_cos).(2*(k+1)+1) = (-1)|^ (2*(k+1)+1) * (1)|^ (2*(2*(k+1)+1))/((2*(2*(k+1)+1))!) by Def25 .=(-1) * (1)|^ (2*(2*(k+1)+1))/((2*(2*(k+1)+1))!) by Lm12 .=(-1) * 1/((2*(2*(k+1)+1))!) by NEWTON:15 .=(-1)/((2*(2*(k+1)+1))!); then A11: (1 P_cos).(2*(k+1)+1)=-1/((2*(2*(k+1)+1))!) by XCMPLX_1:188; 2*(k+1) < 2*(k+1)+1 by REAL_1:69; then 2*(2*(k+1))<2*(2*(k+1)+1) by REAL_1:70; then A12: (2*(2*(k+1)))! <= (2*(2*(k+1)+1))! by Th42; (2*(2*(k+1)))!>0 by Th42; then 1/((2*(2*(k+1)))!) >= 1/((2*(2*(k+1)+1))!) by A12,REAL_2:152; then A13: 1/((2*(2*(k+1)))!)-1/(2*(2*(k+1)+1)!)>=0 by SQUARE_1:12; ((Partial_Sums(1 P_cos))*bq).(k+1)-((Partial_Sums(1 P_cos))*bq).k = 1/((2*(2*(k+1)))!)-1/((2*(2*(k+1)+1))!) by A9,A10,A11,XCMPLX_0:def 8 ; then ((Partial_Sums(1 P_cos))*bq).(k+1)>=((Partial_Sums(1 P_cos))*bq). k by A13,REAL_2:105; hence thesis by A8,AXIOMS:22; end; for n holds X[n] from Ind(A6,A7); hence thesis; end; hence thesis by A4,A5,Th41; end; then A14: cos.1>0 by AXIOMS:22; A15: sin.1>=5/6 proof A16: (Partial_Sums(1 P_sin))*bq is_subsequence_of Partial_Sums(1 P_sin) by SEQM_3:def 10; A17: Partial_Sums(1 P_sin) is convergent & sin.1=Sum(1 P_sin) by Th39,Th40; then A18: (Partial_Sums(1 P_sin))*bq is convergent by A16,SEQ_4:29; lim ((Partial_Sums(1 P_sin))*bq )=lim(Partial_Sums(1 P_sin)) by A16,A17, SEQ_4:30; then A19: lim ((Partial_Sums(1 P_sin))*bq )= sin.1 by A17,SERIES_1:def 3; for n holds ((Partial_Sums(1 P_sin))*bq).n >=5/6 proof let n; defpred X[Nat] means ((Partial_Sums(1 P_sin))*bq).$1 >= 5/6; ((Partial_Sums(1 P_sin))*bq).0=(Partial_Sums(1 P_sin)).(bq.0) by SEQM_3:31 .= (Partial_Sums(1 P_sin)).(2*0+1) by Lm11 .=(Partial_Sums(1 P_sin)).0+(1 P_sin).(0+1) by SERIES_1:def 1 .= (1 P_sin).0 +(1 P_sin).(0+1) by SERIES_1:def 1 .=(-1)|^ 0 * (1)|^ (2*0+1)/((2*0+1)!)+(1 P_sin).(1) by Def24 .= (-1)|^ 0 * (1)|^ (2*0+1)/((2*0+1)!)+ (-1)|^ 1 * (1)|^ (2*1+1)/((2*1+1)!) by Def24 .=1* (1)|^ (2*0+1)/((2*0+1)!)+ (-1)|^ 1 * (1)|^ (2*1+1)/((2*1+1)!) by Lm12 .=1/((0+1)!)+(-1)|^ 1 * (1)|^ (2*1+1)/((2*1+1)!) by Lm12 .=1/(0!*1)+(-1)|^ 1 * (1)|^ (2*1+1)/((2*1+1)!) by NEWTON:21 .=1+ (-1)* (1)|^ (2*1+1)/((2*1+1)!) by Lm12,NEWTON:18 .=1+ (-1)*1/((2*1+1)!) by NEWTON:15 .=1+ (-1)/((2*1)!*(2*1+1)) by NEWTON:21 .=1+(-1)/(1! * (1+1)*3) by NEWTON:21 .=1+(-1)/((0+1)! *(2*3)) by XCMPLX_1:4 .=1+(-1)/(1* 1 *6) by NEWTON:18,21 .=5/6; then A20: X[0]; A21: for k st X[k] holds X[k+1] proof let k; assume A22: ((Partial_Sums(1 P_sin))*bq).k >= 5/6; ((Partial_Sums(1 P_sin))*bq).(k+1) =(Partial_Sums(1 P_sin)).(bq.(k+1)) by SEQM_3:31 .=(Partial_Sums(1 P_sin)).(2*(k+1)+1) by Lm11 .=(Partial_Sums(1 P_sin)).(2*(k+1)) +(1 P_sin).(2*(k+1)+1) by SERIES_1:def 1 .= (Partial_Sums(1 P_sin)).(2*k+2*1) +(1 P_sin).(2*(k+1)+1) by XCMPLX_1:8 .= (Partial_Sums(1 P_sin)).(2*k+(1+1))+(1 P_sin).(2*(k+1)+1) .=(Partial_Sums(1 P_sin)).(2*k+1+1)+(1 P_sin).(2*(k+1)+1) by XCMPLX_1:1 .=(Partial_Sums(1 P_sin)).(2*k+1) + (1 P_sin).(2*k+1+1)+ (1 P_sin).(2*(k+1)+1) by SERIES_1:def 1 .= (Partial_Sums(1 P_sin)).(bq.k)+ (1 P_sin).(2*k+1+1)+ (1 P_sin).(2*(k+1)+1) by Lm11 .=((Partial_Sums(1 P_sin))*bq).k+ (1 P_sin).(2*k+1+1)+ (1 P_sin).(2*(k+1)+1) by SEQM_3:31; then A23: ((Partial_Sums(1 P_sin))*bq).(k+1)-((Partial_Sums(1 P_sin))*bq).k = ((Partial_Sums(1 P_sin))*bq).k+((1 P_sin).(2*k+1+1) + (1 P_sin).(2*(k+1)+1))-((Partial_Sums(1 P_sin))*bq).k by XCMPLX_1: 1 .=((Partial_Sums(1 P_sin))*bq).k-((Partial_Sums(1 P_sin))*bq).k +((1 P_sin).(2*k+1+1)+ (1 P_sin).(2*(k+1)+1)) by XCMPLX_1:29 .=0+((1 P_sin).(2*k+1+1)+ (1 P_sin).(2*(k+1)+1)) by XCMPLX_1:14 .=(1 P_sin).(2*k+1+1)+ (1 P_sin).(2*(k+1)+1); A24: (1 P_sin).(2*k+1+1)=(1 P_sin).(2*k+(1+1)) by XCMPLX_1:1 .=(1 P_sin).(2*k+2*1) .=(1 P_sin).(2*(k+1)) by XCMPLX_1:8 .=(-1)|^ (2*(k+1)) * (1)|^ (2*(2*(k+1))+1)/((2*(2*(k+1))+1)!) by Def24 .=(1)* (1)|^ (2*(2*(k+1))+1)/((2*(2*(k+1))+1)!) by Lm12 .=1/((2*(2*(k+1))+1)!) by NEWTON:15; (1 P_sin).(2*(k+1)+1) = (-1)|^ (2*(k+1)+1) * (1)|^ (2*(2*(k+1)+1)+1)/((2*(2*(k+1)+1)+1)!) by Def24 .=(-1) * (1)|^ (2*(2*(k+1)+1)+1)/((2*(2*(k+1)+1)+1)!) by Lm12 .=(-1) * 1/((2*(2*(k+1)+1)+1)!) by NEWTON:15 .=(-1)/((2*(2*(k+1)+1)+1)!); then A25: (1 P_sin).(2*(k+1)+1)=-1/((2*(2*(k+1)+1)+1)!) by XCMPLX_1:188; 2*(k+1) < 2*(k+1)+1 by REAL_1:69; then 2*(2*(k+1))<2*(2*(k+1)+1) by REAL_1:70; then 2*(2*(k+1))+1<2*(2*(k+1)+1) +1 by REAL_1:53; then A26: (2*(2*(k+1))+1)! <= (2*(2*(k+1)+1)+1)! by Th42; (2*(2*(k+1))+1)!>0 by Th42; then 1/((2*(2*(k+1))+1)!) >= 1/((2*(2*(k+1)+1)+1)!) by A26,REAL_2:152 ; then A27: 1/((2*(2*(k+1))+1)!)-1/((2*(2*(k+1)+1)+1)!)>=0 by SQUARE_1:12; ((Partial_Sums(1 P_sin))*bq).(k+1)-((Partial_Sums(1 P_sin))*bq).k = 1/((2*(2*(k+1))+1)!)-1/((2*(2*(k+1)+1)+1)!) by A23,A24,A25,XCMPLX_0:def 8; then ((Partial_Sums(1 P_sin))*bq).(k+1)>=((Partial_Sums(1 P_sin))*bq) .k by A27,REAL_2:105; hence thesis by A22,AXIOMS:22; end; for n holds X[n] from Ind(A20,A21); hence thesis; end; hence thesis by A18,A19,Th41; end; then A28: sin.1>0 by AXIOMS:22; sin.1>cos.1 proof A29: 0 <=(cos.(1))^2 by SQUARE_1:72; (cos.(1))^2+(sin.(1))^2=1 by Th31; then A30: (sin.(1))^2=1-(cos.(1))^2 by XCMPLX_1:26; A31: (sin.(1))^2>=(25/36) by A15,Lm13,SQUARE_1:77; then A32: 1-(1-(cos.(1))^2)<=1-25/36 by A30,REAL_2:106; 1-(1-(cos.(1))^2)= 1-1+(cos.(1))^2 by XCMPLX_1:37 .=(cos.(1))^2; then (cos.(1))^2<25/36 by A32,AXIOMS:22; then (sin.(1))^2> (cos.(1))^2 by A31,AXIOMS:22; then A33: sqrt(cos.(1))^2<sqrt(sin.(1))^2 by A29,SQUARE_1:95; sqrt(cos.(1))^2 = cos.1 by A14,SQUARE_1:89; hence thesis by A28,A33,SQUARE_1:89; end; hence thesis by A1,AXIOMS:22; end; theorem Th48:for th holds th ExpSeq=Re([*th,0*] ExpSeq) proof let th; for n holds (th ExpSeq).n=Re([*th,0*] ExpSeq).n proof let n; Re([*th,0*] ExpSeq).n= Re ([*th,0*] ExpSeq.n) by COMSEQ_3:def 3 .=Re([*th,0*] #N n /(n!c )) by Def8 .=Re([*(th|^ n) /(n!),0*]) by Th45 .=(th|^ n) /(n!) by COMPLEX1:7 .=(th ExpSeq).n by Def9; hence thesis; end; hence thesis by FUNCT_2:113; end; theorem Th49: for th holds (th ExpSeq) is summable & Sum(th ExpSeq)=Re(Sum([*th,0*] ExpSeq)) proof let th; A1: Re([*th,0*] ExpSeq) is summable & Sum([*th,0*] ExpSeq)=[*Sum(Re ([*th,0*] ExpSeq)),Sum(Im ([*th,0*] ExpSeq))*] by COMSEQ_3:54; Sum(th ExpSeq)=Sum(Re ([*th,0*] ExpSeq)) by Th48; hence thesis by A1,Th48,COMPLEX1:7; end; Lm14: for z,n holds z* (z#N n)=z #N (n+1) &z ExpSeq.1=z&z ExpSeq.0=1r&z #N1=z &|.z #N n.|=|.z.||^n proof let z,n; A1: z* (z#N n)=z*(z GeoSeq.n) by COMSEQ_3:def 2 .=z GeoSeq.(n+1) by COMSEQ_3:def 1 .=z #N (n+1) by COMSEQ_3:def 2; A2: z #N 1=z GeoSeq.(0+1) by COMSEQ_3:def 2 .=z GeoSeq.0 * z by COMSEQ_3:def 1 .=1r* z by COMSEQ_3:def 1 .=z by COMPLEX1:29; then A3: z ExpSeq.1= z/(1!c) by Def8 .=z/[*1,0*] by Th37,NEWTON:19 .=z by COMPLEX1:85,L1; A4: z ExpSeq.0=z#N 0/ (0!c) by Def8 .=1r/1r by Th1,COMSEQ_3:11 .=1r by COMPLEX1:85; |.z #N n.|=|.z.||^ n proof defpred X[Nat] means |.z #N $1.|=|.z.||^ $1; |.z #N 0 .|=|.z GeoSeq.0 .| by COMSEQ_3:def 2 .=1 by COMPLEX1:134,COMSEQ_3:def 1; then A5: X[0] by Lm12; A6: for k st X[k] holds X[k+1] proof let k such that A7: |.z #N k.|=|.z.||^ k; |.z #N (k+1).|=|.z GeoSeq.(k+1).| by COMSEQ_3:def 2 .=|.z*(z GeoSeq.k).| by COMSEQ_3:def 1 .=|.z*(z#N k).| by COMSEQ_3:def 2 .=|.z.||^ k *|.z.| by A7,COMPLEX1:151 .=|.z.||^(k+1) by NEWTON:11; hence thesis; end; for n holds X[n] from Ind(A5,A6); hence thesis; end; hence thesis by A1,A2,A3,A4; end; Lm15: for th holds Sum([*th,0*] ExpSeq)=[*Sum(th ExpSeq),0*] proof let th; A1: for n holds Im(Partial_Sums([*th,0*] ExpSeq)).n=0 proof defpred X[Nat] means Im(Partial_Sums([*th,0*] ExpSeq)).$1=0; Im(Partial_Sums([*th,0*] ExpSeq)).0 =Im(Partial_Sums([*th,0*] ExpSeq).0) by COMSEQ_3:def 4 .=Im(([*th,0*] ExpSeq).0) by COMSEQ_3:def 7 .=0 by Lm14,COMPLEX1:15; then A2: X[0]; A3: for n st X[n] holds X[n+1] proof let n such that A4: Im(Partial_Sums([*th,0*] ExpSeq)).n=0; Im(Partial_Sums([*th,0*] ExpSeq)).(n+1) =Im(Partial_Sums([*th,0*] ExpSeq).(n+1)) by COMSEQ_3:def 4 .=Im(Partial_Sums([*th,0*] ExpSeq).n+([*th,0*] ExpSeq).(n+1)) by COMSEQ_3:def 7 .=Im(Partial_Sums([*th,0*] ExpSeq).n)+Im(([*th,0*] ExpSeq).(n+1)) by COMPLEX1:19 .=0+Im(([*th,0*] ExpSeq).(n+1)) by A4,COMSEQ_3:def 4 .=Im(([*th,0*] #N(n+1))/((n+1)!c)) by Def8 .=Im([*(th|^ (n+1)) /((n+1)!),0*]) by Th45 .=0 by COMPLEX1:7; hence thesis; end; for n holds X[n] from Ind(A2,A3); hence thesis; end; then Im(Partial_Sums([*th,0*] ExpSeq)) is constant by SEQM_3:def 6; then A5: lim(Im(Partial_Sums([*th,0*] ExpSeq))) =Im(Partial_Sums([*th,0*] ExpSeq)).0 by SEQ_4:41 .=0 by A1; A6: Im(Sum([*th,0*] ExpSeq)) =Im(lim(Partial_Sums([*th,0*] ExpSeq))) by COMSEQ_3:def 8 .=0 by A5,COMSEQ_3:41; Sum([*th,0*] ExpSeq) =[*Re(Sum([*th,0*] ExpSeq)),Im(Sum([*th,0*] ExpSeq))*] by COMPLEX1:8 .=[*Sum(th ExpSeq),0*] by A6,Th49; hence thesis; end; theorem Th50: for p,q holds Sum((p+q) ExpSeq)= (Sum(p ExpSeq))*(Sum(q ExpSeq)) proof let p,q; Sum((p+q) ExpSeq)=Re(Sum([*p+q,0+0*] ExpSeq)) by Th49 .=Re(Sum(([*p,0*]+[*q,0*]) ExpSeq)) by Lm13 .=Re((Sum([*p,0*] ExpSeq)) *(Sum([*q,0*] ExpSeq))) by Lm4 .=Re([*Re(Sum([*p,0*] ExpSeq)),Im(Sum([*p,0*] ExpSeq))*] *(Sum([*q,0*] ExpSeq))) by COMPLEX1:8 .= Re([*Re(Sum([*p,0*] ExpSeq)),Im(Sum([*p,0*] ExpSeq))*]* [*Re(Sum([*q,0*] ExpSeq)),Im(Sum([*q,0*] ExpSeq))*]) by COMPLEX1:8 .= Re([*Sum(p ExpSeq),Im(Sum([*p,0*] ExpSeq))*]* [*Re(Sum([*q,0*] ExpSeq)),Im(Sum([*q,0*] ExpSeq))*]) by Th49 .= Re([*Sum(p ExpSeq), 0*]* [*Re(Sum([*q,0*] ExpSeq)),Im(Sum([*q,0*] ExpSeq))*]) by Th46 .= Re([*Sum(p ExpSeq), 0*]* [*Sum(q ExpSeq), Im(Sum([*q,0*] ExpSeq))*]) by Th49 .= Re([*Sum(p ExpSeq), 0*]* [*Sum(q ExpSeq),0*]) by Th46 .=Re([*(Sum(p ExpSeq))*(Sum(q ExpSeq)),0*(Sum(q ExpSeq))*]) by Lm10 .=(Sum(p ExpSeq))*(Sum(q ExpSeq)) by COMPLEX1:7; hence thesis; end; definition func exp -> PartFunc of REAL, REAL means :Def26: dom it= REAL & for d being real number holds it.d=Sum(d ExpSeq); existence proof defpred X[set] means $1 in REAL; deffunc U(Element of REAL) = Sum($1 ExpSeq); consider f being PartFunc of REAL, REAL such that A1: for d be Element of REAL holds d in dom f iff X[d] and A2: for d be Element of REAL st d in dom f holds f/.d = U(d) from LambdaPFD; take f; dom(f)=REAL &for d be real number holds f.d = Sum(d ExpSeq) proof A3: dom(f)=REAL proof A4: dom(f) c=REAL by RELSET_1:12; for x be set st x in REAL holds x in dom f by A1; then REAL c=dom(f) by TARSKI:def 3; hence dom(f)=REAL by A4,XBOOLE_0:def 10; end; for d be real number holds f.d = Sum(d ExpSeq) proof let d be real number; A5: d is Real by XREAL_0:def 1; then A6: d in dom f by A1; then f/.d = Sum(d ExpSeq) by A2,A5; hence f.d = Sum(d ExpSeq) by A6,FINSEQ_4:def 4; end; hence thesis by A3; end; hence thesis; end; uniqueness proof let f1,f2 be PartFunc of REAL, REAL; assume A7: dom f1= REAL & for d being real number holds f1.d=Sum(d ExpSeq); assume A8: dom f2= REAL & for d being real number holds f2.d=Sum(d ExpSeq); for d being Element of REAL st d in REAL holds f1.d = f2.d proof let d be Element of REAL such that d in REAL; thus f1.d=Sum(d ExpSeq) by A7 .=f2.d by A8; end; hence f1=f2 by A7,A8,PARTFUN1:34; end; end; definition let th be real number; func exp th equals:Def27: exp.th; correctness; end; definition let th be real number; cluster exp th -> real; correctness proof exp th = exp.th by Def27; hence thesis; end; end; definition let th be Real; redefine func exp th -> Real; correctness by XREAL_0:def 1; end; theorem Th51: dom(exp)=REAL by Def26; canceled; theorem Th53: for th holds exp.th = Re(Sum([*th,0*] ExpSeq)) proof let th; exp.th = Sum(th ExpSeq) by Def26; hence thesis by Th49; end; theorem exp([*th,0*])=[*exp(th ),0*] proof thus exp([*th,0*])=Sum([*th,0*] ExpSeq) by Lm5 .=[*Sum(th ExpSeq),0*] by Lm15 .=[*exp.(th ),0*] by Def26 .=[*exp(th ),0*] by Def27; end; Lm16:for p,q holds exp.(p+q) = exp.p * exp.q proof let p,q; exp.(p+q) = Sum((p+q) ExpSeq) by Def26 .= (Sum(p ExpSeq))*(Sum(q ExpSeq)) by Th50 .=exp.p *(Sum(q ExpSeq)) by Def26 .=exp.p * exp.q by Def26; hence thesis; end; theorem exp(p+q) = exp(p) * exp(q) proof thus exp(p+q) = exp.(p+q) by Def27 .=exp.p * exp.q by Lm16 .=exp.p *exp(q) by Def27 .=exp(p) * exp(q) by Def27; end; Lm17: exp.0 =1 proof exp.0 = Sum(0 ExpSeq) by Def26 .=1 by Th10,Th49,COMPLEX1:15,L0; hence thesis; end; theorem exp(0) =1 by Def27,Lm17; theorem Th57: for th st th >0 holds exp.th >=1 proof let th such that A1: th >0; A2:for n holds Partial_Sums(th ExpSeq).n>=1 proof defpred X[Nat] means Partial_Sums(th ExpSeq).$1>=1; Partial_Sums(th ExpSeq).0=(th ExpSeq).0 by SERIES_1:def 1 .=th |^ 0 /(0!) by Def9 .=1 by Lm12,NEWTON:18; then A3: X[0]; A4: for n st X[n] holds X[n+1] proof let n; assume A5: Partial_Sums(th ExpSeq).n>=1; A6: Partial_Sums(th ExpSeq).(n+1) =Partial_Sums(th ExpSeq).n+(th ExpSeq).(n+1) by SERIES_1:def 1 .=Partial_Sums(th ExpSeq).n+th |^(n+1)/((n+1)!) by Def9; A7: th |^(n+1) >0 by A1,PREPOWER:13; (n+1)!>0 by Th42; then th |^(n+1)/((n+1)!)>0 by A7,REAL_2:127; then Partial_Sums(th ExpSeq).n+th |^(n+1)/((n+1)!)>Partial_Sums(th ExpSeq).n by REAL_1:69; hence thesis by A5,A6,AXIOMS:22; end; for n holds X[n] from Ind(A3,A4); hence thesis; end; (th ExpSeq) is summable by Th49; then Partial_Sums(th ExpSeq) is convergent& lim(Partial_Sums(th ExpSeq))=Sum(th ExpSeq) by SERIES_1:def 2,def 3; then Sum(th ExpSeq)>=1 by A2,Th41; hence thesis by Def26; end; theorem Th58: for th st th <0 holds 0<exp.th & exp.th <=1 proof let th; assume th <0; then -th >0 by REAL_1:26,50; then A1: exp.(-th)>=1 by Th57; then A2: exp.(-th)> 0 by AXIOMS:22; exp.(-th)*exp.th=exp.(-th+th) by Lm16 .=1 by Lm17,XCMPLX_0:def 6; then A3:exp.th=1/(exp.(-th)) by XCMPLX_1:74; hence 0<exp.th by A2,REAL_2:127; thus exp.th <=1 by A1,A3,REAL_2:164; end; theorem Th59: for th holds exp.th>0 proof let th; now per cases; suppose th=0; hence exp.th>0 by Lm17; suppose A1: th<>0; now per cases by A1; suppose th<0; hence exp.th>0 by Th58; suppose th>0; then exp.th >=1 by Th57; hence exp.th>0 by AXIOMS:22; end; hence exp.th>0; end; hence thesis; end; theorem for th holds exp(th)>0 proof let th; exp(th)=exp.(th) by Def27; hence thesis by Th59; end; begin ::Differential of sin, cos, and Exponential Function definition let z be Element of COMPLEX; deffunc U(Nat) = (z#N($1+1))/(($1+2)!c); func z P_dt -> Complex_Sequence means :Def28: for n holds it.n = (z#N(n+1))/((n+2)!c); existence proof thus ex s being Complex_Sequence st for n holds s.n = U(n) from ExComplexSeq; end; uniqueness proof thus for s1,s2 being Complex_Sequence st (for x being Nat holds s1.x = U(x)) & (for x being Nat holds s2.x = U(x)) holds s1 = s2 from FuncDefUniq; end; deffunc U(Nat) = (z#N($1))/(($1+2)!c); func z P_t -> Complex_Sequence means for n holds it.n = (z#N(n))/((n+2)!c); existence proof thus ex s being Complex_Sequence st for n holds s.n = U(n) from ExComplexSeq; end; uniqueness proof thus for s1,s2 being Complex_Sequence st (for x being Nat holds s1.x = U(x)) & (for x being Nat holds s2.x = U(x)) holds s1 = s2 from FuncDefUniq; end; end; Lm18: for z,p holds Re([*0,p*]*z)=-p*Im z & Im([*0,p*]*z)=p*Re z &Re([*p,0*]*z)=p*Re z & Im([*p,0*]*z)=p*Im z proof let z,p; A1: ([*0,p*]*z)=([*0,p*]*[*Re z,Im z*]) by COMPLEX1:8 .=([*-p* Im z,p*Re z*]) by Lm10; ([*p,0*]*z)=([*p,0*]*[*Re z,Im z*]) by COMPLEX1:8 .=([*p* Re z,p*Im z*]) by Lm10; hence thesis by A1,COMPLEX1:7; end; Lm19: for z,p st p>0 holds Re(z/[*0,p*])=Im z /p & Im(z/[*0,p*])=-Re z /p &|.z/[*p,0*].|=|.z.|/p proof let z,p such that A1: p>0; A2: Re[*0,p*]=0 & Im[*0,p*]=p&Re[*p,0*]=p&Im[*p,0*]=0 by COMPLEX1:7; then A3: z/[*0,p*] =[*(Re z * 0+Im z * p)/((0)+(p)^2), (0* Im z- Re z * p)/((0)+(p)^2)*] by COMPLEX1:def 14,SQUARE_1:60 .=[*(Im z * p)/((p)^2), (-Re z * p)/((p)^2)*] by XCMPLX_1:150 .=[*(Im z * p)/((p)^2), (-Re z * p)/(p*p)*] by SQUARE_1:def 3 .=[*(Im z * p)/(p*p), (-Re z * p)/(p*p)*] by SQUARE_1:def 3 .=[*(Im z * p)/(p*p), ((-Re z) * p)/(p*p)*] by XCMPLX_1:175 .=[*(Im z * p)/(p*p),(-Re z) /p *] by A1,XCMPLX_1:92 .=[*(Im z * p)/(p*p),-Re z/p *] by XCMPLX_1:188 .=[*Im z /p,-Re z /p *] by A1,XCMPLX_1:92; [*p,0*]<>0c by A1,ARYTM_0:def 7; then |.z/[*p,0*].|=|.z.|/|.[*p,0*].| by COMPLEX1:153 .=|.z.|/sqrt((p)^2 + (0)^2) by A2,COMPLEX1:def 16 .=|.z.|/sqrt((p)^2) by SQUARE_1:60; hence thesis by A1,A3,COMPLEX1:7,SQUARE_1:89; end; theorem Th61: for z holds z P_dt is absolutely_summable proof let z; Partial_Sums(|.z P_dt.|) is bounded_above proof ex r st for n holds Partial_Sums(|.z P_dt.|).n<r proof A1: for n holds Partial_Sums(|.z P_dt.|).n<Partial_Sums(|.z ExpSeq.|).(n+1) proof let n; Partial_Sums(|.z P_dt.|).0=|.z P_dt.|.0 by SERIES_1:def 1 .=|.z P_dt.0 .| by COMSEQ_1:def 14 .=|.(z#N(0+1))/((0+2)!c).| by Def28 .=|.z/((2)!c).| by Lm14 .=|.z/[*2,0*].| by Th37,NEWTON:20; then A2: Partial_Sums(|.z P_dt.|).0=|.z.|/2 by Lm19; Partial_Sums(|.z ExpSeq.|).(0+1) =Partial_Sums(|.z ExpSeq.|).0+|.z ExpSeq.|.(0+1) by SERIES_1:def 1 .=|.z ExpSeq.|.0+|.z ExpSeq.|.1 by SERIES_1:def 1 .=|.z ExpSeq.|.0+|.z ExpSeq.1 .| by COMSEQ_1:def 14 .=|.z ExpSeq.0 .|+|.z ExpSeq.1 .| by COMSEQ_1:def 14 .=|.z ExpSeq.0 .|+|.z .| by Lm14 .=1+|.z .| by Lm14,COMPLEX1:134; then A3: Partial_Sums(|.z ExpSeq.|).(0+1)-Partial_Sums(|.z P_dt.|).0 =1+(|.z .| - |.z.|/2) by A2,XCMPLX_1:29; |.z.|=|.z.|/2+|.z.|/2 by XCMPLX_1:66; then A4: Partial_Sums(|.z ExpSeq.|).(0+1)-Partial_Sums(|.z P_dt.|).0 =1+|.z .|/2 by A3,XCMPLX_1:26; A5: 1+|.z.|/2>|.z.|/2 by REAL_1:69; defpred X[Nat] means Partial_Sums(|.z P_dt.|).$1 <Partial_Sums(|.z ExpSeq.|).($1+1); 0 <= |.z.| by COMPLEX1:132; then |.z.|/2>=0 by REAL_2:125; then A6: X[0] by A4,A5,REAL_2:106; A7: for n st X[n] holds X[n+1] proof let n such that A8: Partial_Sums(|.z P_dt.|).n <Partial_Sums(|.z ExpSeq.|).(n+1); A9:Partial_Sums(|.z P_dt.|).(n+1) =Partial_Sums(|.z P_dt.|).n+|.z P_dt.|.(n+1) by SERIES_1:def 1 .=Partial_Sums(|.z P_dt.|).n+|.z P_dt.(n+1).| by COMSEQ_1:def 14 .=Partial_Sums(|.z P_dt.|).n+|.(z#N((n+1)+1))/(((n+1)+2)!c).| by Def28 .=Partial_Sums(|.z P_dt.|).n+|.(z#N((n+1)+1))/((n+(1+2))!c).| by XCMPLX_1:1 .=Partial_Sums(|.z P_dt.|).n+|.(z#N(n+(1+1)))/((n+(1+2))!c).| by XCMPLX_1:1 .=Partial_Sums(|.z P_dt.|).n+|.(z#N(n+2))/[*(n+3)!,0*].| by Th37; (n+3)!>0 by Th42; then A10: Partial_Sums(|.z P_dt.|).(n+1) =Partial_Sums(|.z P_dt.|).n+|.(z#N(n+2)).|/((n+3)!) by A9,Lm19; A11: Partial_Sums(|.z ExpSeq.|).((n+1)+1) =Partial_Sums(|.z ExpSeq.|).(n+1)+|.z ExpSeq.|.((n+1)+1) by SERIES_1:def 1 .= Partial_Sums(|.z ExpSeq.|).(n+1)+|.z ExpSeq.|.(n+(1+1)) by XCMPLX_1: 1 .=Partial_Sums(|.z ExpSeq.|).(n+1)+|.z ExpSeq.(n+2).| by COMSEQ_1:def 14 .=Partial_Sums(|.z ExpSeq.|).(n+1)+|.(z#N(n+2))/((n+2)!c).| by Def8 .=Partial_Sums(|.z ExpSeq.|).(n+1)+|.(z#N(n+2))/[*(n+2)!,0*].| by Th37; (n+2)!>0 by Th42; then A12: Partial_Sums(|.z ExpSeq.|).((n+1)+1) =Partial_Sums(|.z ExpSeq.|).(n+1)+|.(z#N(n+2)).|/((n+2)!) by A11,Lm19; (n+2)<(n+3) by REAL_1:53; then A13:0<(n+2)! & (n+2)!<=(n+3)! by Th42; |.(z#N(n+2)).|>=0 by COMPLEX1:132; then |.(z#N(n+2)).|/((n+2)!)>=|.(z#N(n+2)).|/((n+3)!) by A13,REAL_2:201 ; then A14: Partial_Sums(|.z P_dt.|).n+|.(z#N(n+2)).|/((n+3)!)<= Partial_Sums(|.z P_dt.|).n+|.(z#N(n+2)).|/((n+2)!) by AXIOMS:24; Partial_Sums(|.z P_dt.|).n+|.(z#N(n+2)).|/((n+2)!)< Partial_Sums(|.z ExpSeq.|).(n+1)+|.(z#N(n+2)).|/((n+2)!) by A8,REAL_1:53; hence thesis by A10,A12,A14,AXIOMS:22; end; for n holds X[n] from Ind(A6,A7); hence thesis; end; consider r be real number such that A15:for n holds Partial_Sums(|.z ExpSeq.|).n<r by SEQ_2:def 3; A16: for n holds Partial_Sums(|.z P_dt.|).n<r proof let n; A17: Partial_Sums(|.z P_dt.|).n<Partial_Sums(|.z ExpSeq.|). (n+1) by A1; Partial_Sums(|.z ExpSeq.|).(n+1)<r by A15; hence thesis by A17,AXIOMS:22; end; take r; thus thesis by A16,XREAL_0:def 1; end; hence thesis by SEQ_2:def 3; end; hence thesis by COMSEQ_3:62; end; theorem Th62: for z holds z*(Sum(z P_dt))=(Sum(z ExpSeq))-1r-z proof let z; A1:for z holds z (#) (z P_dt)=(z ExpSeq)^\ 2 proof let z; for n holds (z(#)(z P_dt)).n=((z ExpSeq)^\ 2).n proof let n; (z(#)(z P_dt)).n=z*(z P_dt).(n) by COMSEQ_1:def 7 .=z*((z#N(n+1))/((n+2)!c)) by Def28; then (z(#)(z P_dt)).n= (z*(z#N(n+1)))/((n+2)!c) by XCMPLX_1:75 .=(z#N(n+1+1))/((n+2)!c) by Lm14 .=(z#N(n+(1+1)))/((n+2)!c) by XCMPLX_1:1 .=z ExpSeq.(n+2) by Def8 .=((z ExpSeq)^\ 2).n by COMSEQ_3:def 6; hence thesis; end; hence thesis by COMSEQ_1:6; end; Sum(z ExpSeq)= Partial_Sums(z ExpSeq).1 + Sum(z ExpSeq^\(1+1)) by COMSEQ_3: 61 .=Partial_Sums(z ExpSeq).1 + Sum(z ExpSeq^\(2)); then Sum(z ExpSeq)= Partial_Sums(z ExpSeq).1 + Sum(z (#) (z P_dt)) by A1; then A2: Sum(z (#) (z P_dt))=Sum(z ExpSeq) - Partial_Sums(z ExpSeq).(0+1) by XCMPLX_1:26 .=Sum(z ExpSeq)-(Partial_Sums(z ExpSeq).0+z ExpSeq.1) by COMSEQ_3:def 7 .=Sum(z ExpSeq)-(z ExpSeq.0+z ExpSeq.1) by COMSEQ_3:def 7 .=Sum(z ExpSeq)-(1r+z ExpSeq.1) by Lm14 .=Sum(z ExpSeq)-(1r+z) by Lm14 .=(Sum(z ExpSeq))-1r-z by XCMPLX_1:36; reconsider BBB=z P_dt as absolutely_summable Complex_Sequence by Th61; BBB is summable; hence thesis by A2,COMSEQ_3:57; end; theorem Th63: for p st p>0 holds ex q st q>0 & for z st |.z.|<q holds |.(Sum(z P_dt)).|<p proof A1: for z holds |.(Sum(z P_dt)).| <= Sum (|.z P_dt.|) proof let z; A2: for k holds |.Partial_Sums(z P_dt).|.k <= Partial_Sums(|.z P_dt.|).k proof let k; |.Partial_Sums(z P_dt).k.|=|.Partial_Sums(z P_dt).|.k by COMSEQ_1:def 14 ; hence thesis by COMSEQ_3:30; end; z P_dt is absolutely_summable by Th61; then |.z P_dt.| is summable by COMSEQ_3:def 11; then A3: Partial_Sums(|.z P_dt.|) is convergent by SERIES_1:def 2; z P_dt is absolutely_summable by Th61; then A4: z P_dt is summable by COMSEQ_3:64; then A5: Partial_Sums(z P_dt) is convergent Complex_Sequence by COMSEQ_3:def 10; reconsider PS = Partial_Sums(z P_dt) as convergent Complex_Sequence by A4, COMSEQ_3:def 10; A6: |.PS.| is convergent; A7: lim|.Partial_Sums(z P_dt).|=|.lim(Partial_Sums(z P_dt)).| by A5,COMSEQ_2:11; lim|.Partial_Sums(z P_dt).|<=lim(Partial_Sums(|.z P_dt.|)) by A2,A3,A6, SEQ_2:32; then |.lim(Partial_Sums(z P_dt)).|<=Sum (|.z P_dt.|) by A7,SERIES_1:def 3; hence thesis by COMSEQ_3:def 8; end; A8: for z,n holds |.z P_dt.|.n<=|.z.|*|.z.| GeoSeq.n proof let z,n; A9:|.z P_dt.|.n=|.z P_dt.n.| by COMSEQ_1:def 14 .=|.(z#N(n+1))/((n+2)!c).| by Def28 .=|.(z#N(n+1))/[*(n+2)!,0*].| by Th37; (n+2)!>0 by Th42; then A10: |.z P_dt.|.n=|.(z#N(n+1)).|/((n+2)!) by A9,Lm19 .=|.z.||^(n+1)/((n+2)!) by Lm14; A11: |.z.|*|.z.| GeoSeq.n=|.z.|* (|.z.||^ n) by PREPOWER:def 1 .=|.z.||^(n+1) by NEWTON:11; n+2-1=n+(2-1) by XCMPLX_1:29 .=n+1; then 0<=n+2-1 by NAT_1:18; then 1<=n+2 by REAL_2:105; then 0< n+2 by AXIOMS:22; then A12: (n+2)!>=1 by Th42,NEWTON:18; |.z.|>=0 by COMPLEX1:132; then |.z.||^(n+1) >=0 by POWER:3; then |.z.||^(n+1)/1>=|.z.||^(n+1)/((n+2)!) by A12,REAL_2:201; hence thesis by A10,A11; end; let p; assume A13: p>0; then A14: p+1>0 by Lm13; consider q such that A15: q=p/(p+1); p+1>p by REAL_1:69; then A16: q <1 by A13,A15,REAL_2:142; A17: for z st |.z.|<q holds |.(Sum(z P_dt)).|<p proof let z; assume A18: |.z.|<q; then A19: |.z.|<1 by A16,AXIOMS:22; abs(|.z.|)<1 proof 0<=|.z.| by COMPLEX1:132; hence thesis by A19,ABSVALUE:def 1; end; then A20: |.z.| GeoSeq is summable & Sum(|.z.| GeoSeq) = 1/(1- |.z.|) by SERIES_1:28; then A21: |.z.|(#)|.z.| GeoSeq is summable & Sum(|.z.|(#)|.z.| GeoSeq) =|.z.|*Sum(|.z.| GeoSeq) by SERIES_1:13; A22: for n holds |.z P_dt.|.n<=(|.z.|(#)|.z.| GeoSeq).n proof let n; |.z P_dt.|.n<=|.z.|*|.z.| GeoSeq.n by A8; hence thesis by SEQ_1:13; end; for n holds 0<=|.z P_dt.|.n proof let n; |.z P_dt.|.n=|.z P_dt.n.| by COMSEQ_1:def 14; hence thesis by COMPLEX1:132; end; then A23:(|.z P_dt.|) is summable & Sum(|.z P_dt.|)<=Sum(|.z.|(#)|.z.| GeoSeq) by A21,A22,SERIES_1:24; A24: Sum(|.z.|(#)|.z.| GeoSeq) =|.z.|/(1- |.z.|) by A20,A21,XCMPLX_1:100 ; |.z.|/(1- |.z.|)<p proof A25: |.z.|*(p+1)<(p/(p+1))*(p+1) by A14,A15,A18,REAL_1:70; A26:(p/(p+1))*(p+1)=p by A14,XCMPLX_1:88; |.z.|*(p+1)=|.z.|*p+|.z.|*1 by XCMPLX_1:8 .=p*|.z.|+|.z.|; then A27: p*|.z.|+|.z.|-p*|.z.|<p-p*|.z.| by A25,A26,REAL_1:54; A28: p*|.z.|+|.z.|-p*|.z.|=p*|.z.|-p*|.z.|+|.z.| by XCMPLX_1:29 .=0+|.z.| by XCMPLX_1:14 .=|.z.|; A29: p-p*|.z.|= p*1 -p*|.z.| .=p*(1- |.z.|) by XCMPLX_1:40; A30: 1- |.z.|>0 by A19,SQUARE_1:11; then |.z.|/(1- |.z.|)< p*(1- |.z.|)/(1- |.z.|) by A27,A28,A29, REAL_1:73; hence thesis by A30,XCMPLX_1:90; end; then Sum(|.z P_dt.|)<p & |.(Sum(z P_dt)).|<=Sum (|.z P_dt.|) by A1,A23,A24,AXIOMS:22; hence thesis by AXIOMS:22; end; take q; thus thesis by A13,A14,A15,A17,REAL_2:127; end; theorem Th64: for z,z1 holds (Sum((z1+z) ExpSeq))-(Sum(z1 ExpSeq)) =(Sum(z1 ExpSeq))*z+z*(Sum(z P_dt))*(Sum(z1 ExpSeq)) proof let z,z1; (Sum((z1+z) ExpSeq))-(Sum(z1 ExpSeq)) = (Sum(z1 ExpSeq))*(Sum(z ExpSeq))-(Sum(z1 ExpSeq)) by Lm4 .=(Sum(z1 ExpSeq))*(Sum(z ExpSeq))-(Sum(z1 ExpSeq))*1r by COMPLEX1:29 .=(Sum(z1 ExpSeq))*((Sum(z ExpSeq))-1r) by XCMPLX_1:40 .=(Sum(z1 ExpSeq))*(((Sum(z ExpSeq))-1r)-z+z) by XCMPLX_1:27 .=(Sum(z1 ExpSeq))* (z*(Sum(z P_dt))+z) by Th62 .=(Sum(z1 ExpSeq))*z +z*(Sum(z P_dt))*(Sum(z1 ExpSeq)) by XCMPLX_1:8; hence thesis; end; theorem Th65: for p,q holds cos.(p+q)-cos.p= -q*sin.p -q*Im((Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) proof let p,q; cos.(p+q)-cos.p=cos.(p+q)-Re(Sum([*0,p*] ExpSeq)) by Def22 .=Re(Sum([*0,p+q*] ExpSeq))-Re(Sum([*0,p*] ExpSeq)) by Def22 .=Re(Sum([*0+0,p+q*] ExpSeq)-Sum([*0,p*] ExpSeq)) by COMPLEX1:48 .=Re(Sum(([*0,p*]+[*0,q*]) ExpSeq)-Sum([*0,p*] ExpSeq)) by Lm13 .=Re((Sum([*0,p*] ExpSeq))*[*0,q*] +[*0,q*]*(Sum([*0,q*] P_dt))*(Sum([*0,p*] ExpSeq))) by Th64 .=Re([*cos.p,sin.p*]*[*0,q*]+[*0,q*]*(Sum([*0,q*] P_dt))*(Sum ([*0,p*] ExpSeq))) by Lm6 .= Re([*cos.p,sin.p*]*[*0,q*]+[*0,q*]*(Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by Lm6 .= Re([*cos.p,sin.p*]*[*0,q*])+ Re([*0,q*]*(Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by COMPLEX1:19 .=Re[*-q*sin.p,q*cos.p*]+Re([*0,q*]*(Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by Lm10 .= -q*sin.p +Re([*0,q*]*(Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by COMPLEX1:7 .=-q*sin.p+Re([*0,q*]*((Sum([*0,q*] P_dt))* [*cos.p,sin.p*])) by XCMPLX_1:4 .=-q*sin.p+-q*Im((Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by Lm18 .=-q*sin.p-q*Im((Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by XCMPLX_0:def 8; hence thesis; end; theorem Th66: for p,q holds sin.(p+q)-sin.p= q*cos.p+q*Re((Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) proof let p,q; sin.(p+q)-sin.p=sin.(p+q)-Im(Sum([*0,p*] ExpSeq)) by Def20 .=Im(Sum([*0,p+q*] ExpSeq))-Im(Sum([*0,p*] ExpSeq)) by Def20 .=Im(Sum([*0+0,p+q*] ExpSeq)-Sum([*0,p*] ExpSeq)) by COMPLEX1:48 .=Im(Sum(([*0,p*]+[*0,q*]) ExpSeq)-Sum([*0,p*] ExpSeq)) by Lm13 .=Im((Sum([*0,p*] ExpSeq))*[*0,q*] +[*0,q*]*(Sum([*0,q*] P_dt))*(Sum([*0,p*] ExpSeq))) by Th64 .=Im([*cos.p,sin.p*]*[*0,q*]+[*0,q*]*(Sum([*0,q*] P_dt))*(Sum ([*0,p*] ExpSeq))) by Lm6 .= Im([*cos.p,sin.p*]*[*0,q*]+[*0,q*]*(Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by Lm6 .= Im([*cos.p,sin.p*]*[*0,q*])+ Im([*0,q*]*(Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by COMPLEX1:19 .=Im[*-q*sin.p,q*cos.p*]+Im([*0,q*]*(Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by Lm10 .= q*cos.p +Im([*0,q*]*(Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by COMPLEX1:7 .=q*cos.p+Im([*0,q*]*((Sum([*0,q*] P_dt))* [*cos.p,sin.p*])) by XCMPLX_1:4 .=q*cos.p+q*Re((Sum([*0,q*] P_dt))* [*cos.p,sin.p*]) by Lm18; hence thesis; end; theorem Th67: for p,q holds exp.(p+q)-exp.p= q* (exp.p)+q*exp.p*Re((Sum([*q,0*] P_dt))) proof let p,q; exp.(p+q)-exp.p=exp.(p+q)-Re(Sum([*p,0*] ExpSeq)) by Th53 .=Re(Sum([*p+q,0*] ExpSeq))-Re(Sum([*p,0*] ExpSeq)) by Th53 .=Re(Sum([*p+q,0+0*] ExpSeq)-Sum([*p,0*] ExpSeq)) by COMPLEX1:48 .=Re(Sum(([*p,0*]+[*q,0*]) ExpSeq)-Sum([*p,0*] ExpSeq)) by Lm13 .=Re((Sum([*p,0*] ExpSeq))*[*q,0*] +[*q,0*]*(Sum([*q,0*] P_dt))*(Sum([*p,0*] ExpSeq))) by Th64 .=Re((Sum([*p,0*] ExpSeq))*[*q,0*])+ Re([*q,0*]*(Sum([*q,0*] P_dt))*(Sum([*p,0*] ExpSeq))) by COMPLEX1:19 .=q*Re(Sum([*p,0*] ExpSeq))+ Re([*q,0*]*(Sum([*q,0*] P_dt))*(Sum([*p,0*] ExpSeq))) by Lm18 .=q* (exp.p)+ Re([*q,0*]*(Sum([*q,0*] P_dt))*(Sum([*p,0*] ExpSeq))) by Th53 .=q* (exp.p)+ Re([*q,0*]*((Sum([*q,0*] P_dt))*(Sum([*p,0*] ExpSeq)))) by XCMPLX_1:4 .=q* (exp.p)+ q*Re((Sum([*q,0*] P_dt))*(Sum([*p,0*] ExpSeq))) by Lm18 .=q* (exp.p)+ q*Re((Sum([*q,0*] P_dt))*[*Sum(p ExpSeq),0*]) by Lm15 .=q* (exp.p)+q*Re((Sum([*q,0*] P_dt))*[*exp.p,0*]) by Def26 .=q* (exp.p)+q*(exp.p*Re((Sum([*q,0*] P_dt)))) by Lm18 .=q* (exp.p)+q*exp.p*Re((Sum([*q,0*] P_dt))) by XCMPLX_1:4; hence thesis; end; theorem Th68: for p holds cos is_differentiable_in p & diff(cos,p)=-sin.p proof let p; defpred X[set] means $1 in REAL; deffunc U(Element of REAL) = - $1* Im((Sum([*0,$1*] P_dt))* [*cos.p,sin.p*]); consider C_r being PartFunc of REAL, REAL such that A1: for th be Real holds th in dom C_r iff X[th] and A2: for th be Real st th in dom C_r holds C_r/.th = U(th) from LambdaPFD; A3:dom C_r=REAL proof A4: dom(C_r) c=REAL by RELSET_1:12; for x be set st x in REAL holds x in dom C_r by A1; then REAL c=dom(C_r) by TARSKI:def 3; hence dom(C_r)=REAL by A4,XBOOLE_0:def 10; end; then A5: C_r is total by PARTFUN1:def 4; A6: C_r.d = - d* Im((Sum([*0,d*] P_dt))* [*cos.p,sin.p*]) proof A7: d in dom C_r by A1; then C_r/.d = -d* Im((Sum([*0,d*] P_dt))* [*cos.p,sin.p*]) by A2; hence C_r.d = -d* Im((Sum([*0,d*] P_dt))* [*cos.p,sin.p*]) by A7,FINSEQ_4:def 4; end; C_r is REST-like PartFunc of REAL,REAL proof for hy1 holds (hy1")(#)(C_r*hy1) is convergent & lim ((hy1")(#)(C_r*hy1)) = 0 proof let hy1; A8: for n holds ((hy1")(#)(C_r*hy1)).n =-Im((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]) proof let n; A9: ((hy1")(#)(C_r*hy1)).n=(hy1".n)*((C_r*hy1).n) by SEQ_1:12 .=(hy1.n)"*((C_r*hy1).n) by SEQ_1:def 8; rng hy1 c= dom C_r by A3; then A10: ((hy1")(#)(C_r*hy1)).n= (hy1.n)"*(C_r.(hy1.n)) by A9,RFUNCT_2:21 .=(hy1.n)"*( -(hy1.n)* Im((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*])) by A6 .= -(hy1.n)"*((hy1.n)* Im((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*])) by XCMPLX_1:175 .=-(hy1.n)"*(hy1.n)* Im((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]) by XCMPLX_1:4; hy1 is_not_0 by FDIFF_1:def 1; then hy1.n<>0 by SEQ_1:7; then ((hy1")(#)(C_r*hy1)).n =-1*Im((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]) by A10,XCMPLX_0:def 7 .=-Im((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]); hence thesis; end; deffunc U(Real) = -Im((Sum([*0,(hy1.$1)*] P_dt))* [*cos.p,sin.p*]); consider rseq such that A11: for n holds rseq.n= U(n) from ExRealSeq; deffunc U(Nat) = (Sum([*0,(hy1.$1)*] P_dt))* [*cos.p,sin.p*]; consider cq1 such that A12: for n holds cq1.n=U(n) from ExComplexSeq; A13:cq1 is convergent & lim(cq1)=0c proof A14: for q be Real st q>0 holds ex k st for m st k<=m holds |.cq1.m-0c.|<q proof let q be Real such that A15: q>0; ex k st for m st k<=m holds |.cq1.m-0c.|<q proof consider r such that A16: r>0 & for z st |.z.|<r holds |.(Sum (z P_dt)).|<q by A15,Th63; hy1 is convergent&lim(hy1)=0 by FDIFF_1:def 1; then consider k such that A17: for m st k<=m holds abs(hy1.m-0)<r by A16,SEQ_2:def 7; A18: now let m such that A19: k<=m; A20: |.cq1.m-0c.|= |.(Sum([*0,(hy1.m)*] P_dt))* [*cos.p,sin.p*] .| by A12 .= |.(Sum([*0,(hy1.m)*] P_dt)).|* |.[*cos.p,sin.p*].| by COMPLEX1:151 .= |.(Sum([*0,(hy1.m)*] P_dt)).|* |.Sum([*0,p*] ExpSeq ).| by Lm6 .=|.(Sum([*0,(hy1.m)*] P_dt)).|*1 by Lm8 .=|.(Sum([*0,(hy1.m)*] P_dt)).|; A21: abs(hy1.m-0)<r by A17,A19; Re[*0,(hy1.m)*]=0 & Im[*0,(hy1.m)*]=hy1.m by COMPLEX1:7; then |.[*0,(hy1.m)*].| = sqrt((0)^2 + (hy1.m)^2) by COMPLEX1:def 16 .=abs(hy1.m) by SQUARE_1:60,91; hence |.cq1.m-0c.|<q by A16,A20,A21; end; take k; thus for m st k<=m holds |.cq1.m-0c.|<q by A18; end; hence thesis; end; then cq1 is convergent by COMSEQ_2:def 4; hence thesis by A14,COMSEQ_2:def 5; end; then A22: -cq1 is convergent by COMSEQ_2:21; A23: lim(-cq1)=0c by A13,COMSEQ_2:22,REAL_1:26; A24: for n holds Im(-cq1).n= rseq.n proof A25: for n holds Im(-cq1).n=-Im((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]) proof let n; Im(-cq1).n=Im((-cq1).n) by COMSEQ_3:def 4 .=Im(-cq1.n) by COMSEQ_1:def 9 .=Im(-(Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]) by A12 .=-Im((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]) by COMPLEX1:34; hence thesis; end; let n; rseq.n=-Im((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]) by A11; hence thesis by A25; end; rseq=(hy1")(#)(C_r*hy1) proof for n holds rseq.n=((hy1")(#)(C_r*hy1)).n proof let n; rseq.n=-Im((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]) by A11; hence thesis by A8; end; hence thesis by FUNCT_2:113; end; then (hy1")(#)(C_r*hy1)=Im(-cq1) by A24,FUNCT_2:113; hence thesis by A22,A23,COMPLEX1:12,COMSEQ_3:41; end; hence thesis by A5,FDIFF_1:def 3; end; then reconsider PR = C_r as REST-like PartFunc of REAL,REAL; reconsider PR as REST; defpred X[set] means $1 in REAL; deffunc U(Element of REAL) = -$1*sin.p; consider CL being PartFunc of REAL, REAL such that A26: for th be Real holds th in dom CL iff X[th] and A27: for th be Real st th in dom CL holds CL/.th= U(th) from LambdaPFD; A28: for d be real number holds CL.d = -d*sin.p proof let d be real number; A29: d is Real by XREAL_0:def 1; then A30: d in dom CL by A26; then CL/.d = -d*sin.p by A27,A29; hence CL.d = -d*sin.p by A30,FINSEQ_4:def 4; end; dom CL=REAL proof A31: dom(CL) c=REAL by RELSET_1:12; for x be set st x in REAL holds x in dom CL by A26; then REAL c=dom(CL) by TARSKI:def 3; hence dom(CL)=REAL by A31,XBOOLE_0:def 10; end; then A32: CL is total by PARTFUN1:def 4; CL is linear PartFunc of REAL,REAL proof ex r be Real st for q be Real holds CL.q=r*q proof A33: for q be Real holds CL.q=(-sin.p)*q proof let q be Real; CL.q= -q*sin.p by A28 .=(-sin.p)*q by XCMPLX_1:175; hence thesis; end; take (-sin.p); thus thesis by A33; end; hence thesis by A32,FDIFF_1:def 4; end; then reconsider PL = CL as linear PartFunc of REAL,REAL; reconsider PL as LINEAR; A34: ex N being Neighbourhood of p st N c= dom cos & for r st r in N holds cos.r - cos.p = PL.(r-p) + PR.(r-p) proof A35: for r st r in ].p-1,p+1 .[ holds cos.r - cos.p = PL.(r-p) + PR.(r-p) proof let r; r=r+p-p by XCMPLX_1:26 .=p+(r-p) by XCMPLX_1:29; then cos.r - cos.p =-(r-p)*sin.p -(r-p)*Im((Sum([*0,(r-p)*] P_dt))* [*cos.p,sin.p*]) by Th65 .=-(r-p)*sin.p+(-(r-p)*Im((Sum([*0,(r-p)*] P_dt))*[*cos.p,sin.p*])) by XCMPLX_0:def 8 .=-(r-p)*sin.p+C_r.(r-p) by A6 .=PL.(r-p) + PR.(r-p) by A28; hence thesis; end; take ].p-1,p+1 .[; thus thesis by A35,Th27,RCOMP_1:def 7; end; then A36: cos is_differentiable_in p by FDIFF_1:def 5; PL.1= -1*sin.p by A28 .=-sin.p; hence thesis by A34,A36,FDIFF_1:def 6; end; theorem Th69: for p holds sin is_differentiable_in p & diff(sin,p)=cos.p proof let p; defpred X[set] means $1 in REAL; deffunc U(Element of REAL) = $1 *Re((Sum([*0,$1*] P_dt))* [*cos.p,sin.p*]); consider C_r being PartFunc of REAL, REAL such that A1: for th be Real holds th in dom C_r iff X[th] and A2: for th be Real st th in dom C_r holds C_r/.th = U(th) from LambdaPFD; A3:dom C_r=REAL proof A4: dom(C_r) c=REAL by RELSET_1:12; for x be set st x in REAL holds x in dom C_r by A1; then REAL c=dom(C_r) by TARSKI:def 3; hence dom(C_r)=REAL by A4,XBOOLE_0:def 10; end; then A5: C_r is total by PARTFUN1:def 4; A6: C_r.d = d*Re((Sum([*0,d*] P_dt))* [*cos.p,sin.p*]) proof A7: d in dom C_r by A1; then C_r/.d = d*Re((Sum([*0,d*] P_dt))* [*cos.p,sin.p*]) by A2; hence C_r.d = d*Re((Sum([*0,d*] P_dt))* [*cos.p,sin.p*]) by A7,FINSEQ_4:def 4; end; C_r is REST-like PartFunc of REAL,REAL proof for hy1 holds (hy1")(#)(C_r*hy1) is convergent & lim ((hy1")(#)(C_r*hy1)) = 0 proof let hy1; A8: for n holds ((hy1")(#)(C_r*hy1)).n =Re((Sum([*0,hy1.n*] P_dt))* [*cos.p,sin.p*]) proof let n; A9: ((hy1")(#)(C_r*hy1)).n=(hy1".n)*((C_r*hy1).n) by SEQ_1:12 .=(hy1.n)"*((C_r*hy1).n) by SEQ_1:def 8; rng hy1 c= dom C_r by A3; then A10: ((hy1")(#)(C_r*hy1)).n= (hy1.n)"*(C_r.(hy1.n)) by A9,RFUNCT_2:21 .=(hy1.n)"*( (hy1.n)*Re((Sum([*0,hy1.n*] P_dt))* [*cos.p,sin.p*])) by A6 .=(hy1.n)"*(hy1.n)* Re((Sum([*0,hy1.n*] P_dt))* [*cos.p,sin.p*]) by XCMPLX_1:4; hy1 is_not_0 by FDIFF_1:def 1; then hy1.n<>0 by SEQ_1:7; then ((hy1")(#)(C_r*hy1)).n =1*Re((Sum([*0,hy1.n*] P_dt))* [*cos.p,sin.p*]) by A10,XCMPLX_0:def 7 .=Re((Sum([*0,hy1.n*] P_dt))* [*cos.p,sin.p*]); hence thesis; end; deffunc U(Real) = Re((Sum([*0,hy1.$1*] P_dt))* [*cos.p,sin.p*]); consider rseq such that A11: for n holds rseq.n= U(n) from ExRealSeq; deffunc U(Nat) = (Sum([*0,(hy1.$1)*] P_dt))* [*cos.p,sin.p*]; consider cq1 such that A12: for n holds cq1.n= U(n) from ExComplexSeq; A13:cq1 is convergent & lim(cq1)=0c proof A14: for q be Real st q>0 holds ex k st for m st k<=m holds |.cq1.m-0c.|<q proof let q be Real such that A15: q>0; ex k st for m st k<=m holds |.cq1.m-0c.|<q proof consider r such that A16: r>0 & for z st |.z.|<r holds |.(Sum (z P_dt)).|<q by A15,Th63; hy1 is convergent&lim(hy1)=0 by FDIFF_1:def 1; then consider k such that A17: for m st k<=m holds abs(hy1.m-0)<r by A16,SEQ_2:def 7; A18: now let m such that A19: k<=m; A20: |.cq1.m-0c.|= |.(Sum([*0,(hy1.m)*] P_dt))* [*cos.p,sin.p*].| by A12 .= |.(Sum([*0,(hy1.m)*] P_dt)).|* |.[*cos.p,sin.p*].| by COMPLEX1:151 .= |.(Sum([*0,(hy1.m)*] P_dt)).|* |.Sum([*0,p*] ExpSeq ).| by Lm6 .=|.(Sum([*0,(hy1.m)*] P_dt)).|*1 by Lm8 .=|.(Sum([*0,(hy1.m)*] P_dt)).|; A21: abs(hy1.m-0)<r by A17,A19; Re[*0,(hy1.m)*]=0 & Im[*0,(hy1.m)*]=hy1.m by COMPLEX1:7; then |.[*0,(hy1.m)*].| = sqrt((0)^2 + (hy1.m)^2) by COMPLEX1:def 16 .=abs(hy1.m) by SQUARE_1:60,91; hence |.cq1.m-0c.|<q by A16,A20,A21; end; take k; thus for m st k<=m holds |.cq1.m-0c.|<q by A18; end; hence thesis; end; then cq1 is convergent by COMSEQ_2:def 4; hence thesis by A14,COMSEQ_2:def 5; end; A22: for n holds Re(cq1).n= rseq.n proof let n; Re(cq1).n=Re((cq1).n) by COMSEQ_3:def 3 .=Re((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]) by A12; hence thesis by A11; end; rseq=(hy1")(#)(C_r*hy1) proof for n holds rseq.n=((hy1")(#)(C_r*hy1)).n proof let n; rseq.n=Re((Sum([*0,(hy1.n)*] P_dt))* [*cos.p,sin.p*]) by A11 ; hence thesis by A8; end; hence thesis by FUNCT_2:113; end; then (hy1")(#)(C_r*hy1)=Re(cq1) by A22,FUNCT_2:113; hence thesis by A13,COMPLEX1:12,COMSEQ_3:41; end; hence thesis by A5,FDIFF_1:def 3; end; then reconsider PR = C_r as REST-like PartFunc of REAL,REAL; reconsider PR as REST; defpred X[set] means $1 in REAL; deffunc U(Element of REAL) = $1*cos.p; consider CL being PartFunc of REAL, REAL such that A23: for th be Real holds th in dom CL iff X[th] and A24: for th be Real st th in dom CL holds CL/.th=U(th) from LambdaPFD; A25: for d be real number holds CL.d = d*cos.p proof let d be real number; A26: d is Real by XREAL_0:def 1; then A27: d in dom CL by A23; then CL/.d = d*cos.p by A24,A26; hence CL.d = d*cos.p by A27,FINSEQ_4:def 4; end; dom CL=REAL proof A28: dom(CL) c=REAL by RELSET_1:12; for x be set st x in REAL holds x in dom CL by A23; then REAL c=dom(CL) by TARSKI:def 3; hence dom(CL)=REAL by A28,XBOOLE_0:def 10; end; then A29: CL is total by PARTFUN1:def 4; CL is linear PartFunc of REAL,REAL proof ex r be Real st for q be Real holds CL.q=r*q proof take (cos.p); thus thesis by A25; end; hence thesis by A29,FDIFF_1:def 4; end; then reconsider PL = CL as linear PartFunc of REAL,REAL; reconsider PL as LINEAR; A30: ex N being Neighbourhood of p st N c= dom sin & for r st r in N holds sin.r - sin.p = PL.(r-p) + PR.(r-p) proof A31: for r st r in ].p-1,p+1 .[ holds sin.r - sin.p = PL.(r-p) + PR.(r-p) proof let r; r=r+p-p by XCMPLX_1:26 .=p+(r-p) by XCMPLX_1:29; then sin.r - sin.p =(r-p)*cos.p +(r-p)*Re((Sum([*0,(r-p)*] P_dt))* [*cos.p,sin.p*]) by Th66 .=(r-p)*cos.p +C_r.(r-p) by A6 .=PL.(r-p) + PR.(r-p) by A25; hence thesis; end; take ].p-1,p+1 .[; thus thesis by A31,Th27,RCOMP_1:def 7; end; then A32: sin is_differentiable_in p by FDIFF_1:def 5; PL.1= 1*cos.p by A25; hence thesis by A30,A32,FDIFF_1:def 6; end; theorem Th70: for p holds exp is_differentiable_in p & diff(exp,p)=exp.p proof let p; defpred X[set] means $1 in REAL; deffunc U(Element of REAL) = $1 *exp.p*Re((Sum([*$1,0*] P_dt))); consider C_r being PartFunc of REAL, REAL such that A1: for th be Real holds th in dom C_r iff X[th] and A2: for th be Real st th in dom C_r holds C_r/.th =U(th) from LambdaPFD; A3:dom C_r=REAL proof A4: dom(C_r) c=REAL by RELSET_1:12; for x be set st x in REAL holds x in dom C_r by A1; then REAL c=dom(C_r) by TARSKI:def 3; hence dom(C_r)=REAL by A4,XBOOLE_0:def 10; end; then A5: C_r is total by PARTFUN1:def 4; A6: C_r.d = d*exp.p*Re((Sum([*d,0*] P_dt))) proof A7: d in dom C_r by A1; then C_r/.d = d*exp.p*Re((Sum([*d,0*] P_dt))) by A2; hence C_r.d = d*exp.p*Re((Sum([*d,0*] P_dt))) by A7,FINSEQ_4:def 4; end; C_r is REST-like PartFunc of REAL,REAL proof for hy1 holds (hy1")(#)(C_r*hy1) is convergent & lim ((hy1")(#)(C_r*hy1)) = 0 proof let hy1; A8: for n holds ((hy1")(#)(C_r*hy1)).n =exp.p*Re((Sum([*(hy1.n),0*] P_dt))) proof let n; A9: ((hy1")(#)(C_r*hy1)).n=(hy1".n)*((C_r*hy1).n) by SEQ_1:12 .=(hy1.n)"*((C_r*hy1).n) by SEQ_1:def 8; rng hy1 c= dom C_r by A3; then A10: ((hy1")(#)(C_r*hy1)).n= (hy1.n)"*(C_r.(hy1.n)) by A9,RFUNCT_2:21 .=(hy1.n)"*( (hy1.n)*exp.p*Re((Sum([*(hy1.n),0*] P_dt)))) by A6 .=(hy1.n)"*( (hy1.n)*(exp.p*Re((Sum([*(hy1.n),0*] P_dt))))) by XCMPLX_1:4 .=(hy1.n)"*(hy1.n)* (exp.p*Re((Sum([*(hy1.n),0*] P_dt)))) by XCMPLX_1:4; hy1 is_not_0 by FDIFF_1:def 1; then hy1.n<>0 by SEQ_1:7; then ((hy1")(#)(C_r*hy1)).n =1*(exp.p*Re((Sum([*(hy1.n),0*] P_dt)))) by A10,XCMPLX_0:def 7 .=exp.p*Re((Sum([*(hy1.n),0*] P_dt))); hence thesis; end; deffunc U(Real) = exp.p*Re((Sum([*(hy1.$1),0*] P_dt))); consider rseq such that A11: for n holds rseq.n= U(n) from ExRealSeq; deffunc U(Nat) = (Sum([*(hy1.$1),0*] P_dt))*[*exp.p,0*]; consider cq1 such that A12: for n holds cq1.n= U(n) from ExComplexSeq; A13:cq1 is convergent & lim(cq1)=0c proof A14: for q be Real st q>0 holds ex k st for m st k<=m holds |.cq1.m-0c.|<q proof let q be Real such that A15: q>0; ex k st for m st k<=m holds |.cq1.m-0c.|<q proof exp.p>0 by Th59; then q/exp.p>0 by A15,REAL_2:127; then consider r such that A16: r>0 & for z st |.z.|<r holds |.(Sum(z P_dt)).|<q/exp.p by Th63; hy1 is convergent&lim(hy1)=0 by FDIFF_1:def 1; then consider k such that A17: for m st k<=m holds abs(hy1.m-0)<r by A16,SEQ_2:def 7; A18: now let m such that A19: k<=m; A20: |.cq1.m-0c.|= |.(Sum([*(hy1.m),0*] P_dt))* [*exp.p,0*].| by A12 .= |.(Sum([*(hy1.m),0*] P_dt)).|* |.[*exp.p,0*].| by COMPLEX1:151 .= |.(Sum([*(hy1.m),0*] P_dt)).|* sqrt((Re [*exp.p,0*])^2 + (Im [*exp.p,0*])^2) by COMPLEX1:def 16; A21: Re[*exp.p,0*]=exp.p & Im[*exp.p,0*]=0 by COMPLEX1:7; A22: exp.p>0 by Th59; then A23: |.cq1.m-0c.| =|.(Sum([*(hy1.m),0*] P_dt)).|* (exp.p) by A20,A21,SQUARE_1:60,89; A24: abs(hy1.m-0)<r by A17,A19; Re[*(hy1.m),0*]=hy1.m & Im[*(hy1.m),0*]=0 by COMPLEX1:7; then |.[*(hy1.m),0*].|= sqrt( (hy1.m)^2+(0)^2 ) by COMPLEX1: def 16 .=abs(hy1.m) by SQUARE_1:60,91; then |.(Sum([*(hy1.m),0*] P_dt)).|<q/exp.p by A16,A24; then |.cq1.m-0c.|<q/exp.p * exp.p by A22,A23,REAL_1:70; hence |.cq1.m-0c.|<q by A22,XCMPLX_1:88; end; take k; thus for m st k<=m holds |.cq1.m-0c.|<q by A18; end; hence thesis; end; then cq1 is convergent by COMSEQ_2:def 4; hence thesis by A14,COMSEQ_2:def 5; end; A25: for n holds Re(cq1).n= rseq.n proof A26: for n holds Re(cq1).n=exp.p*Re((Sum([*(hy1.n),0*] P_dt))) proof let n; Re(cq1).n=Re(cq1.n) by COMSEQ_3:def 3 .=Re((Sum([*(hy1.n),0*] P_dt))*[*exp.p,0*]) by A12 .=exp.p*Re((Sum([*(hy1.n),0*] P_dt))) by Lm18; hence thesis; end; let n; rseq.n=exp.p*Re((Sum([*(hy1.n),0*] P_dt))) by A11; hence thesis by A26; end; rseq=(hy1")(#)(C_r*hy1) proof for n holds rseq.n=((hy1")(#)(C_r*hy1)).n proof let n; rseq.n=exp.p*Re((Sum([*(hy1.n),0*] P_dt))) by A11; hence thesis by A8; end; hence thesis by FUNCT_2:113; end; then (hy1")(#)(C_r*hy1)=Re(cq1) by A25,FUNCT_2:113; hence thesis by A13,COMPLEX1:12,COMSEQ_3:41; end; hence thesis by A5,FDIFF_1:def 3; end; then reconsider PR = C_r as REST-like PartFunc of REAL,REAL; reconsider PR as REST; defpred X[set] means $1 in REAL; deffunc U(Element of REAL) = $1* (exp.p); consider CL being PartFunc of REAL, REAL such that A27: for th be Real holds th in dom CL iff X[th] and A28: for th be Real st th in dom CL holds CL/.th=U(th) from LambdaPFD; A29: for d be real number holds CL.d = d* (exp.p) proof let d be real number; A30: d is Real by XREAL_0:def 1; then A31: d in dom CL by A27; then CL/.d = d* (exp.p) by A28,A30; hence CL.d =d* (exp.p) by A31,FINSEQ_4:def 4; end; dom CL=REAL proof A32: dom(CL) c=REAL by RELSET_1:12; for x be set st x in REAL holds x in dom CL by A27; then REAL c=dom(CL) by TARSKI:def 3; hence dom(CL)=REAL by A32,XBOOLE_0:def 10; end; then A33: CL is total by PARTFUN1:def 4; CL is linear PartFunc of REAL,REAL proof ex r be Real st for q be Real holds CL.q=r*q proof take (exp.p); thus thesis by A29; end; hence thesis by A33,FDIFF_1:def 4; end; then reconsider PL = CL as linear PartFunc of REAL,REAL; reconsider PL as LINEAR; A34: ex N being Neighbourhood of p st N c= dom exp & for r st r in N holds exp.r - exp.p = PL.(r-p) + PR.(r-p) proof A35: for r st r in ].p-1,p+1 .[ holds exp.r - exp.p = PL.(r-p) + PR.(r-p) proof let r; r=r+p-p by XCMPLX_1:26 .=p+(r-p) by XCMPLX_1:29; then exp.r - exp.p =(r-p)* (exp.p)+(r-p)*exp.p*Re((Sum([*(r-p),0*] P_dt))) by Th67 .=(r-p)* (exp.p)+C_r.(r-p) by A6 .=PL.(r-p) + PR.(r-p) by A29; hence thesis; end; take ].p-1,p+1 .[; thus thesis by A35,Th51,RCOMP_1:def 7; end; then A36: exp is_differentiable_in p by FDIFF_1:def 5; PL.1= 1*exp.p by A29; hence thesis by A34,A36,FDIFF_1:def 6; end; theorem (exp is_differentiable_on REAL) & (for th st th in REAL holds diff(exp,th)=exp.(th)) proof REAL is open Subset of REAL& REAL c=dom exp & for r st r in REAL holds exp is_differentiable_in r by Def26,Th70,FCONT_3:4,SUBSET_1:def 4; hence thesis by Th70,FDIFF_1:16; end; theorem Th72: (cos is_differentiable_on REAL) & (for th st th in REAL holds diff(cos,th)=-sin.(th)) proof REAL is open Subset of REAL& REAL c=dom cos & for r st r in REAL holds cos is_differentiable_in r by Def22,Th68,FCONT_3:4,SUBSET_1:def 4; hence thesis by Th68,FDIFF_1:16; end; theorem Th73: sin is_differentiable_on REAL & (for th holds diff(sin,th)=cos.(th)) proof REAL is open Subset of REAL& REAL c=dom sin & for r st r in REAL holds sin is_differentiable_in r by Def20,Th69,FCONT_3:4,SUBSET_1:def 4; hence thesis by Th69,FDIFF_1:16; end; theorem Th74: for th st th in [.0,1 .] holds 0<cos.(th) & cos.(th)>=1/2 proof let th; assume th in [.0,1 .]; then A1: 0<=th & th<=1 by TOPREAL5:1; A2: (Partial_Sums(th P_cos))*bq is_subsequence_of Partial_Sums(th P_cos) by SEQM_3:def 10; A3: Partial_Sums(th P_cos) is convergent & cos.th=Sum (th P_cos) by Th39,Th40; then A4: (Partial_Sums(th P_cos))*bq is convergent by A2,SEQ_4:29; lim ((Partial_Sums(th P_cos))*bq )=lim(Partial_Sums(th P_cos)) by A2,A3, SEQ_4:30; then A5: lim ((Partial_Sums(th P_cos))*bq )= cos.th by A3,SERIES_1:def 3; for n holds ((Partial_Sums(th P_cos))*bq).n >=1/2 proof let n; A6: ((Partial_Sums(th P_cos))*bq).0=(Partial_Sums(th P_cos)).(bq.0) by SEQM_3:31 .= (Partial_Sums(th P_cos)).(2*0+1) by Lm11 .= (Partial_Sums(th P_cos)).0+(th P_cos).(0+1) by SERIES_1:def 1 .= (th P_cos).0 +(th P_cos).(0+1) by SERIES_1:def 1 .= (-1)|^ 0 * (th)|^ (2*0)/((2*0)!)+(th P_cos).1 by Def25 .= (-1)|^ 0 * (th)|^ (2*0)/((2*0)!)+ (-1)|^ 1 * (th)|^ (2*1)/((2*1)!) by Def25 .= 1* (th)|^ (2*0)/((2*0)!)+ (-1)|^ 1 * (th)|^ (2*1)/((2*1)!) by Lm12 .= 1/1 + (-1)|^ 1 * (th)|^ (2*1)/((2*1)!) by Lm12,NEWTON:18 .= 1+ (-1)* (th)|^ (2*1)/((2*1)!) by Lm12 .= 1+ (-1)*(th*th)/((2*1)!) by Lm12 .= 1+(-(th*th))/2 by NEWTON:20,XCMPLX_1:180 .= 1+ -(th*th)/2 by XCMPLX_1:188 .= 1-(th*th)/2 by XCMPLX_0:def 8 .= 1-(th^2)/2 by SQUARE_1:def 3; A7: 1 - 1/2 = 1/2; defpred X[Nat] means ((Partial_Sums(th P_cos))*bq).$1 >= 1/2; th^2 <= 1^2 by A1,SQUARE_1:77; then th^2 <=1*1 by SQUARE_1:def 3; then (th^2)/2<=1/2 by REAL_1:73; then A8: X[0] by A6,A7,REAL_2:106; A9: for k st X[k] holds X[k+1] proof let k; assume A10: ((Partial_Sums(th P_cos))*bq).k >= 1/2; ((Partial_Sums(th P_cos))*bq).(k+1) =(Partial_Sums(th P_cos)).(bq.(k+1)) by SEQM_3:31 .=(Partial_Sums(th P_cos)).(2*(k+1)+1) by Lm11 .=(Partial_Sums(th P_cos)).(2*(k+1)) +(th P_cos).(2*(k+1)+1) by SERIES_1:def 1 .= (Partial_Sums(th P_cos)).(2*k+2*1) +(th P_cos).(2*(k+1)+1) by XCMPLX_1:8 .= (Partial_Sums(th P_cos)).(2*k+(1+1))+(th P_cos).(2*(k+1)+1) .=(Partial_Sums(th P_cos)).(2*k+1+1)+(th P_cos).(2*(k+1)+1) by XCMPLX_1:1 .=(Partial_Sums(th P_cos)).(2*k+1) + (th P_cos).(2*k+1+1)+ (th P_cos).(2*(k+1)+1) by SERIES_1:def 1 .= (Partial_Sums(th P_cos)).(bq.k)+ (th P_cos).(2*k+1+1)+ (th P_cos).(2*(k+1)+1) by Lm11 .=((Partial_Sums(th P_cos))*bq).k+ (th P_cos).(2*k+1+1)+ (th P_cos).(2*(k+1)+1) by SEQM_3:31; then A11: ((Partial_Sums(th P_cos))*bq).(k+1)-((Partial_Sums(th P_cos))*bq).k = ((Partial_Sums(th P_cos))*bq).k+((th P_cos).(2*k+1+1) + (th P_cos).(2*(k+1)+1))-((Partial_Sums(th P_cos))*bq).k by XCMPLX_1:1 .=((Partial_Sums(th P_cos))*bq).k-((Partial_Sums(th P_cos))*bq).k +((th P_cos).(2*k+1+1)+ (th P_cos).(2*(k+1)+1)) by XCMPLX_1:29 .=0+((th P_cos).(2*k+1+1)+ (th P_cos).(2*(k+1)+1)) by XCMPLX_1:14 .=(th P_cos).(2*k+1+1)+ (th P_cos).(2*(k+1)+1); A12: (th P_cos).(2*k+1+1)=(th P_cos).(2*k+(1+1)) by XCMPLX_1:1 .=(th P_cos).(2*k+2*1) .=(th P_cos).(2*(k+1)) by XCMPLX_1:8 .=(-1)|^ (2*(k+1)) * (th)|^ (2*(2*(k+1)))/((2*(2*(k+1)))!) by Def25 .=(1)* (th)|^ (2*(2*(k+1)))/((2*(2*(k+1)))!) by Lm12 .=(th)|^ (2*(2*(k+1)))/((2*(2*(k+1)))!); (th P_cos).(2*(k+1)+1) = (-1)|^ (2*(k+1)+1) * (th)|^ (2*(2*(k+1)+1))/((2*(2*(k+1)+1))!) by Def25 .=((-1) * (th)|^ (2*(2*(k+1)+1)))/((2*(2*(k+1)+1))!) by Lm12; then A13:(th P_cos).(2*(k+1)+1) =(-1) * ((th)|^ (2*(2*(k+1)+1))/((2*(2*(k+1)+1))!)) by XCMPLX_1:75 .=-(th)|^ (2*(2*(k+1)+1))/((2*(2*(k+1)+1))!) by XCMPLX_1:180; 2*(k+1) < 2*(k+1)+1 by REAL_1:69; then A14: 2*(2*(k+1))<2*(2*(k+1)+1) by REAL_1:70; then A15: (2*(2*(k+1)))! <= (2*(2*(k+1)+1))! by Th42; A16: (th)|^ (2*(2*(k+1)+1)) <= (th)|^ (2*(2*(k+1))) by A1,A14,Th43; A17: 0 <= (th)|^ (2*(2*(k+1)+1)) by POWER:3; A18:(2*(2*(k+1)))!>0 & (2*(2*(k+1)+1))! >0 by Th42; then A19: 1/((2*(2*(k+1)+1))!)<=1/((2*(2*(k+1)))!) by A15,REAL_2:152; 0<1/((2*(2*(k+1)+1))!) by A18,REAL_2:127; then A20: (th)|^ (2*(2*(k+1)+1))*(1/((2*(2*(k+1)+1))!))<= (th)|^ (2*(2*(k+1)))*(1/((2*(2*(k+1)))!)) by A16,A17,A19,REAL_2:197; A21: (th)|^ (2*(2*(k+1)+1))*(1/((2*(2*(k+1)+1))!)) =((th)|^ (2*(2*(k+1)+1))*1)/((2*(2*(k+1)+1))!) by XCMPLX_1:75 .=(th)|^ (2*(2*(k+1)+1))/((2*(2*(k+1)+1))!); (th)|^ (2*(2*(k+1)))*(1/((2*(2*(k+1)))!)) =(th)|^ (2*(2*(k+1)))*1/((2*(2*(k+1)))!) by XCMPLX_1:75; then A22: ((th)|^ (2*(2*(k+1)))*1)/((2*(2*(k+1)))!)- ((th)|^ (2*(2*(k+1)+1))*1)/((2*(2*(k+1)+1))!)>=0 by A20,A21,SQUARE_1: 12; ((Partial_Sums(th P_cos))*bq).(k+1)-((Partial_Sums(th P_cos))*bq).k = ((th)|^ (2*(2*(k+1)))*1)/((2*(2*(k+1)))!)- ((th)|^ (2*(2*(k+1)+1))*1)/((2*(2*(k+1)+1))!) by A11,A12,A13,XCMPLX_0: def 8; then ((Partial_Sums(th P_cos))*bq).(k+1)>=((Partial_Sums(th P_cos))*bq ).k by A22,REAL_2:105; hence thesis by A10,AXIOMS:22; end; for n holds X[n] from Ind(A8,A9); hence thesis; end; then cos.th >= 1/2 by A4,A5,Th41; hence thesis by AXIOMS:22; end; theorem Th75: [.0,1 .] c= dom (sin/cos) & ].0,1 .[c=dom(sin/cos) proof [.0,1 .] c= dom cos \ cos"{0} proof A1: [.0,1 .] \ cos"{0} c=dom cos \ cos"{0} by Th27,XBOOLE_1:33; [.0,1 .] /\ cos"{0}={} proof assume [.0,1 .] /\ cos"{0}<>{}; then consider rr such that A2:rr in [.0,1 .] /\ cos"{0} by XBOOLE_0:def 1; A3:rr in [.0,1 .] & rr in cos"{0} by A2,XBOOLE_0:def 3; then A4:cos.(rr) <>0 by Th74; cos.(rr) in {0} by A3,FUNCT_1:def 13; hence contradiction by A4,TARSKI:def 1; end; then [.0,1 .] misses cos"{0} by XBOOLE_0:def 7; hence thesis by A1,XBOOLE_1:83; end; then [.0,1 .] c= dom sin /\ (dom cos \ cos"{0}) by Th27,XBOOLE_1:19; then A5:[.0,1 .] c= dom (sin/cos) by RFUNCT_1:def 4; ].0,1 .[c=[.0,1 .] by RCOMP_1:15; hence thesis by A5,XBOOLE_1:1; end; Lm20: dom((sin/cos)|[.0,1 .]) = [.0,1 .] & (for th st th in [.0,1 .] holds (sin/cos)|[.0,1 .].th=(sin/cos).th) proof dom((sin/cos)|[.0,1 .])=dom (sin/cos) /\ [.0,1 .] by RELAT_1:90; then dom((sin/cos)|[.0,1 .]) = [.0,1 .] by Th75,XBOOLE_1:28; hence thesis by FUNCT_1:68; end; Lm21: sin/cos is_differentiable_on ].0,1 .[ & for th st th in ].0,1 .[ holds diff(sin/cos,th)>0 proof A1: sin is_differentiable_on ].0,1 .[ by Th73,FDIFF_1:34; A2: cos is_differentiable_on ].0,1 .[ by Th72,FDIFF_1:34; A3:for th be Real st th in ].0,1 .[ holds cos.th<>0 proof let th be Real such that A4: th in ].0,1 .[; ].0,1 .[ c=[.0,1 .] by RCOMP_1:15; hence cos.th<>0 by A4,Th74; end; for th st th in ].0,1 .[ holds diff(sin/cos,th)>0 proof let th such that A5: th in ].0,1 .[; A6: cos is_differentiable_in th by Th68; A7: sin is_differentiable_in th by Th69; A8: cos.th<>0 by A3,A5; then A9: diff(sin/cos,th)=(diff(sin,th)*cos.th-diff(cos,th)*sin.th)/(cos.th) ^2 by A6,A7,FDIFF_2:14 .=(cos.th*cos.th-diff(cos,th)*sin.th)/(cos.th)^2 by Th69 .=(cos.th*cos.th-(-sin.th)*sin.th)/(cos.th)^2 by Th68 .=(cos.th*cos.th--(sin.th)*sin.th)/(cos.th)^2 by XCMPLX_1:175 .=(cos.th*cos.th+(sin.th)*sin.th)/(cos.th)^2 by XCMPLX_1:151 .=((cos.th)^2+(sin.th)*sin.th)/(cos.th)^2 by SQUARE_1:def 3 .=((cos.th)^2+(sin.th)^2)/(cos.th)^2 by SQUARE_1:def 3 .=1/(cos.th)^2 by Th31; (cos.th)^2>0 by A8,SQUARE_1:74; hence thesis by A9,REAL_2:127; end; hence thesis by A1,A2,A3,FDIFF_2:21; end; theorem Th76: sin/cos is_continuous_on [. 0, 1 .] proof for th be real number st th in [.0,1 .] holds (sin/cos)|[.0,1 .] is_continuous_in th proof let th be real number such that A1: th in [.0,1 .]; A2: th is Real by XREAL_0:def 1; A3:[#] REAL = REAL by SUBSET_1:def 4; then sin is_differentiable_in th by A2,Th73,FCONT_3:4,FDIFF_1:16; then A4: sin is_continuous_in th by FDIFF_1:32; cos is_differentiable_in th by A2,A3,Th72,FCONT_3:4,FDIFF_1:16; then A5: cos is_continuous_in th by FDIFF_1:32; cos.(th) <> 0 by A1,Th74; then A6: sin/cos is_continuous_in th by A4,A5,FCONT_1:11; th in dom ((sin/cos)|[.0,1 .]) & for rseq st rng rseq c= dom ((sin/cos)|[.0,1 .]) & rseq is convergent & lim rseq = th holds ((sin/cos)|[.0,1 .])*rseq is convergent & ((sin/cos)|[.0,1 .]).th = lim (((sin/cos)|[.0,1 .])*rseq) proof now let rseq; assume A7: rng rseq c= dom ((sin/cos)|[.0,1 .]) & rseq is convergent & lim rseq = th; then A8:rng rseq c= dom (sin/cos) by Lm20,Th75,XBOOLE_1:1; then A9: (sin/cos)*rseq is convergent & (sin/cos).th = lim ((sin/cos)*rseq) by A6,A7,FCONT_1:def 1; ((sin/cos)|[.0,1 .])*rseq =(sin/cos)*rseq proof now let k1 be Nat; dom (rseq) = NAT by SEQ_1:3; then rseq.k1 in rng rseq by FUNCT_1:def 5; then A10: ((sin/cos)|[.0,1 .]).(rseq.k1)=(sin/cos).(rseq.k1) by A7, Lm20; ((sin/cos)|[.0,1 .]).(rseq.k1)=(((sin/cos)|[.0,1 .])*rseq).k1 by A7,RFUNCT_2:21; hence (((sin/cos)|[.0,1 .])*rseq).k1=((sin/cos)*rseq).k1 by A8,A10,RFUNCT_2:21; end; hence thesis by FUNCT_2:113; end; hence ((sin/cos)|[.0,1 .])*rseq is convergent & ((sin/cos)|[.0,1 .]).th = lim (((sin/cos)|[.0,1 .])*rseq) by A1,A9,Lm20; end; hence thesis by A1,Lm20; end; hence thesis by FCONT_1:def 1; end; hence sin/cos is_continuous_on [. 0, 1 .] by Th75,FCONT_1:def 2; end; theorem Th77: for th1,th2 st th1 in ].0,1 .[ & th2 in ].0,1 .[ & (sin/cos).th1=(sin/cos).th2 holds th1=th2 proof let th1,th2; assume A1: th1 in ].0,1 .[ & th2 in ].0,1 .[ & (sin/cos).(th1)=(sin/cos).(th2); then A2: 0<th1 & th1<1 & 0<th2 & th2<1 by JORDAN6:45; assume A3: th1<>th2; ex th st th in ].0,1 .[ & diff((sin/cos),(th))=0 proof now per cases by A3,REAL_1:def 5; suppose A4: th1<th2; A5: ].th1,th2.[ is open Subset of REAL & ].th1,th2.[c=].0,1 .[& [.th1,th2.]c=[.0,1 .] proof A6: for th be Real st th in ].th1,th2.[ holds th in ].0,1 .[ proof let th be Real; assume th in ].th1,th2.[; then A7: th1<th& th< th2 by JORDAN6:45; then A8: 0< th by A2,AXIOMS:22; th <1 by A2,A7,AXIOMS:22; hence thesis by A8,JORDAN6:45; end; for th be Real st th in [.th1,th2.] holds th in [.0,1 .] proof let th be Real; assume th in [.th1,th2.]; then A9: th1<=th& th<= th2 by TOPREAL5:1; then A10: 0<= th by A2,AXIOMS:22; th <=1 by A2,A9,AXIOMS:22; hence thesis by A10,TOPREAL5:1; end; hence thesis by A6,SUBSET_1:7; end; then A11: (sin/cos) is_differentiable_on ].th1,th2.[ by Lm21,FDIFF_1:34; (sin/cos) is_continuous_on [.th1,th2.] by A5,Th76,FCONT_1:17; then consider r such that A12: r in ].th1,th2.[ & diff((sin/cos),r)=0 by A1,A4,A11,ROLLE:1; take th=r; thus th in ].0,1 .[ & diff((sin/cos),(th))=0 by A5,A12; suppose A13: th2<th1; A14: ].th2,th1 .[ is open Subset of REAL & ].th2,th1 .[c=].0,1 .[& [.th2,th1 .]c=[.0,1 .] proof A15: for th be Real st th in ].th2,th1 .[ holds th in ].0,1 .[ proof let th be Real; assume th in ].th2,th1 .[; then A16: th2<th& th< th1 by JORDAN6:45; then A17: 0< th by A2,AXIOMS:22; th <1 by A2,A16,AXIOMS:22; hence thesis by A17,JORDAN6:45; end; for th be Real st th in [.th2,th1 .] holds th in [.0,1 .] proof let th be Real; assume th in [.th2,th1 .]; then A18: th2<=th& th<= th1 by TOPREAL5:1; then A19: 0<= th by A2,AXIOMS:22; th <=1 by A2,A18,AXIOMS:22; hence thesis by A19,TOPREAL5:1; end; hence thesis by A15,SUBSET_1:7; end; then A20: (sin/cos) is_differentiable_on ].th2,th1 .[ by Lm21, FDIFF_1:34; (sin/cos) is_continuous_on [.th2,th1 .] by A14,Th76,FCONT_1:17; then consider r such that A21: r in ].th2,th1 .[ & diff((sin/cos),r)=0 by A1,A13,A20,ROLLE:1; take th=r; thus th in ].0,1 .[ & diff((sin/cos),(th))=0 by A14,A21; end; hence thesis; end; hence thesis by Lm21; end; Lm22: (sin/cos).(0) =0 & (sin/cos).(1) >1 proof 0 in [.0,1 .] by TOPREAL5:1; then A1: (sin/cos).(0)=(sin.0)* (cos.0)" by Th75,RFUNCT_1:def 4 .=0 by Th33; 1 in [.0,1 .] by TOPREAL5:1; then (sin/cos).(1)=(sin.1)* (cos.1)" by Th75,RFUNCT_1:def 4 .=(sin.1)/ (cos.1) by XCMPLX_0:def 9; hence thesis by A1,Th47,REAL_2:142; end; begin :: Existence of Circle Ratio definition func PI -> real number means :Def30: (sin/cos).(it/4) = 1 & it in ]. 0, 4 .[; existence proof A1: 1 in [.(sin/cos).0,(sin/cos).1 .] proof [.(sin/cos).0,(sin/cos).1 .] = {r : (sin/cos).0<=r & r<= (sin/cos).1 } by RCOMP_1:def 1; hence 1 in [.(sin/cos).0,(sin/cos).1 .] by Lm22; end; (sin/cos).1 > (sin/cos).0 by Lm22,AXIOMS:22; then [.(sin/cos).1,(sin/cos).0 .]= {} by RCOMP_1:13; then 1 in [.(sin/cos).0,(sin/cos).1 .] \/ [.(sin/cos).1,(sin/cos).0 .] by A1; then consider th be Real such that A2: th in [.0, 1 .] & (sin/cos).(th)=1 by Th76,FCONT_2:16; 0<=th & th <= 1 by A2,TOPREAL5:1; then A3: 0 <th & th <1 by A2,Lm22,REAL_1:def 5; take th1 =th*4; thus (sin/cos).(th1/4)=1 by A2,XCMPLX_1:90; 0*4<th*4 & th*4<1*4 by A3,REAL_1:70; hence thesis by JORDAN6:45; end; uniqueness proof let th1,th2 be real number such that A4: (sin/cos).(th1/4) = 1 & th1 in ]. 0, 4 .[ and A5: (sin/cos).(th2/4) = 1 & th2 in ]. 0, 4 .[; th1/4 in ].0,1 .[ & th2/4 in ]. 0, 1 .[ proof 0<th1 & th1 <4 by A4,JORDAN6:45; then 0/4<th1/4 & th1/4 <4/4 by REAL_1:73; hence th1/4 in ]. 0, 1 .[ by JORDAN6:45; 0<th2 & th2 < 4 by A5,JORDAN6:45; then 0/4<th2/4 & th2/4 <4/4 by REAL_1:73; hence th2/4 in ]. 0, 1 .[ by JORDAN6:45; end; then th1/4=th2/4 by A4,A5,Th77; hence th1=th2 by XCMPLX_1:53; end; end; definition redefine func PI -> Real; coherence by XREAL_0:def 1; end; theorem Th78: sin.(PI/4) = cos.(PI/4) proof PI in ].0, 4.[ by Def30; then 0< PI & PI < 4 by JORDAN6:45; then 0/4 <PI/4 & PI/4 < 4/4 by REAL_1:73; then A1: PI/4 in ].0,1 .[ by JORDAN6:45; (sin/cos).(PI/4) =1 by Def30; then sin.(PI/4) * (cos.(PI/4))"=1 by A1,Th75,RFUNCT_1:def 4; hence sin.(PI/4) = cos.(PI/4) by XCMPLX_1:210; end; begin ::Formulas of sin and cos theorem Th79: sin.(th1+th2)=(sin.(th1)) *(cos.(th2))+(cos.(th1)) * (sin.(th2)) & cos.(th1+th2)=(cos.(th1)) *(cos.(th2))-(sin.(th1)) * (sin.(th2)) proof A1: Sum([*0,th1*] ExpSeq ) * Sum([*0,th2*] ExpSeq ) =Sum(([*0,th1*]+[*0,th2*]) ExpSeq ) by Lm4 .=Sum([*0+0, th1+th2*] ExpSeq ) by Lm3 .=[*cos.(th1+th2),sin.(th1+th2)*] by Lm6; Sum(([*0,th1*] ExpSeq) ) * Sum(([*0,th2*] ExpSeq) ) =[*cos.(th1),sin.(th1)*]* Sum(([*0,th2*] ExpSeq) ) by Lm6 .=[*cos.(th1),sin.(th1)*]*[*cos.(th2),sin.(th2)*] by Lm6 .=[*(cos.(th1)) *( cos.(th2))-(sin.(th1)) * (sin.(th2)), (sin.(th1)) * (cos.(th2))+(cos.(th1)) * (sin.(th2))*] by Lm3; hence thesis by A1,ARYTM_0:12; end; theorem sin(th1+th2)=(sin(th1)) *(cos(th2))+(cos(th1)) * (sin(th2)) & cos(th1+th2)=(cos(th1)) *(cos(th2))-(sin(th1)) * (sin(th2)) proof thus sin(th1+th2)=sin.(th1+th2) by Def21 .=(sin.(th1)) *(cos.(th2))+(cos.(th1)) * (sin.(th2)) by Th79 .=(sin(th1)) *(cos.(th2))+(cos.(th1)) * (sin.(th2)) by Def21 .=(sin(th1)) *(cos(th2))+(cos.(th1)) * (sin.(th2)) by Def23 .=(sin(th1)) *(cos(th2))+(cos(th1)) * (sin.(th2)) by Def23 .=(sin(th1)) *(cos(th2))+(cos(th1)) * (sin(th2)) by Def21; thus cos(th1+th2)=cos.(th1+th2) by Def23 .=(cos.(th1)) *(cos.(th2))-(sin.(th1)) * (sin.(th2)) by Th79 .=(cos(th1)) *(cos.(th2))-(sin.(th1)) * (sin.(th2)) by Def23 .=(cos(th1)) *(cos(th2))-(sin.(th1)) * (sin.(th2)) by Def23 .=(cos(th1)) *(cos(th2))-(sin(th1)) * (sin.(th2)) by Def21 .=(cos(th1)) *(cos(th2))-(sin(th1)) * (sin(th2)) by Def21; end; theorem Th81: cos.(PI/2) = 0 & sin.(PI/2) = 1 & cos.(PI) = -1 & sin.(PI) = 0 & cos.(PI+PI/2) = 0 & sin.(PI+PI/2) = -1 & cos.(2 * PI) = 1 & sin.(2 * PI) =0 proof thus A1: cos.(PI/2)=cos.(PI/4+PI/4) by XCMPLX_1:72 .=(cos.(PI/4)) * (cos.(PI/4)) -(cos.(PI/4)) * (cos.(PI/4)) by Th78,Th79 .=0 by XCMPLX_1:14; thus A2: sin.(PI/2)=sin.(PI/4+PI/4) by XCMPLX_1:72 .= (cos.(PI/4)) *( cos.(PI/4)) +(sin.(PI/4)) * (sin.(PI/4)) by Th78,Th79 .=1 by Th31; thus A3: cos.(PI)=cos.(PI/2+PI/2) by XCMPLX_1:66 .=0 * 0-sin.(PI/2) * sin.(PI/2) by A1,Th79 .=-1 by A2; thus A4: sin.(PI)=sin.(PI/2+PI/2) by XCMPLX_1:66 .=(sin.(PI/2)) *( cos.(PI/2)) +(cos.(PI/2) )*( sin.(PI/2)) by Th79 .=0 by A1; thus cos.(PI+PI/2) =(cos.(PI)) *( cos.(PI/2)) -(sin.(PI)) * (sin.(PI/2)) by Th79 .=0 by A1,A4; thus sin.(PI+PI/2) =(sin.(PI) )*( cos.(PI/2)) +(cos.(PI)) *( sin.(PI/2) ) by Th79 .=-1 by A1,A2,A3; thus cos.(2 * PI)=cos.(PI+PI) by XCMPLX_1:11 .=(-1 ) * (-1) -sin.(PI) * sin.(PI) by A3,Th79 .=1 by A4; thus sin.(2 * PI)=sin.(PI+PI) by XCMPLX_1:11 .=(sin.(PI)) * (cos.(PI))+(cos.(PI)) * (sin.(PI)) by Th79 .=0 by A4; end; theorem cos(PI/2) = 0 & sin(PI/2) = 1 & cos(PI) = -1 & sin(PI) = 0 & cos(PI+PI/2) = 0 & sin(PI+PI/2) = -1 & cos(2 * PI) = 1 & sin(2 * PI) =0 by Def21,Def23,Th81; theorem Th83: sin.(th+2 * PI) = sin.th & cos.(th+2 * PI) = cos.th & sin.(PI/2-th) = cos.th & cos.(PI/2-th) = sin.th & sin.(PI/2+th) = cos.th & cos.(PI/2+th) = -sin.th & sin.(PI+th) = -sin.th & cos.(PI+th) = -cos.th proof thus sin.(th+2 * PI)=sin.(th) * 1 +cos.(th) * 0 by Th79,Th81 .=sin.th; thus cos.(th+2 * PI)=cos.(th) * 1 - sin.(th) * 0 by Th79,Th81 .=cos.th; thus sin.(PI/2-th) =sin.(PI/2+(-th)) by XCMPLX_0:def 8 .=(sin.(PI/2) )* (cos.(-th)) + (cos.(PI/2)) *( sin.(-th)) by Th79 .=cos.(th) by Th33,Th81; thus cos.(PI/2-th) =cos.(PI/2+(-th)) by XCMPLX_0:def 8 .=(cos.(PI/2)) * (cos.(-th)) - ( sin.(PI/2)) *( sin.(-th)) by Th79 .=0 - 1 * (-sin.(th)) by Th33,Th81 .=0 + - 1 * (-sin.(th)) by XCMPLX_0:def 8 .=sin.(th); thus sin.(PI/2+th) =1 * cos.(th) + 0 * (sin.(th)) by Th79,Th81 .=cos.(th); thus cos.(PI/2+th) =(cos.(PI/2)) *( cos.(th)) -( sin.(PI/2) )*( sin.(th)) by Th79 .=0 + - 1 * sin.(th) by Th81,XCMPLX_0:def 8 .=-sin.(th); thus sin.(PI+th) =(sin.(PI)) * (cos.(th)) +( cos.(PI) )*( sin.(th)) by Th79 .=0 + -sin.(th) * 1 by Th81,XCMPLX_1:175 .=-sin.(th); thus cos.(PI+th) =(-1) * cos.(th) - 0 * sin.(th) by Th79,Th81 .=-cos.(th) * 1 - 0 by XCMPLX_1:175 .=-cos.(th); end; theorem sin(th+2 * PI) = sin(th) & cos(th+2 * PI) = cos(th) & sin(PI/2-th) = cos(th) & cos(PI/2-th) = sin(th) & sin(PI/2+th) = cos(th) & cos(PI/2+th) = -sin(th) & sin(PI+th) = -sin(th) & cos(PI+th) = -cos(th) proof thus sin(th+2 * PI) =sin.(th+2 * PI) by Def21 .=sin.th by Th83 .=sin(th) by Def21; thus cos(th+2 * PI) = cos.(th+2 * PI) by Def23 .=cos.th by Th83 .=cos(th) by Def23; thus sin(PI/2-th) = sin.(PI/2-th) by Def21 .=cos.(th) by Th83 .=cos(th) by Def23; thus cos(PI/2-th) =cos.(PI/2-th) by Def23 .=sin.(th) by Th83 .= sin(th) by Def21; thus sin(PI/2+th)=sin.(PI/2+th) by Def21 .= cos.th by Th83 .= cos(th) by Def23; thus cos(PI/2+th)=cos.(PI/2+th) by Def23 .= -sin.th by Th83 .= -sin(th) by Def21; thus sin(PI+th)=sin.(PI+th) by Def21 .= -sin.th by Th83 .= -sin(th) by Def21; thus cos(PI+th)=cos.(PI+th) by Def23 .= -cos.th by Th83 .= -cos(th) by Def23; end; Lm23: for th st th in [.0,1 .] holds sin.th>=0 proof let th; assume A1: th in [.0,1 .]; then A2: 0<=th & th<=1 by TOPREAL5:1; sin.th>= sin.0 proof now per cases by A1,TOPREAL5:1; suppose th=0; hence sin.th>= sin.0; suppose A3: 0<th; A4: sin is_differentiable_on ].0,th.[ by Th73,FDIFF_1:34; sin is_continuous_on REAL by Th73,FDIFF_1:33; then sin is_continuous_on [.0,th.] by FCONT_1:17; then consider r be Real such that A5: r in ].0,th.[ & diff(sin,r)=(sin.th-sin.0)/(th-0) by A3,A4,ROLLE:3; A6: diff(sin,r)=cos.r by Th73; 0<r & r < th by A5,JORDAN6:45; then 0<r & r <1 by A2,AXIOMS:22; then r in [.0,1 .] by TOPREAL5:1; then A7: cos.r >0 by Th74; sin.th-sin.0= cos.r* th by A3,A5,A6,XCMPLX_1:88; then sin.th-sin.0 >0 by A3,A7,REAL_2:122; hence sin.th>=sin.0 by REAL_2:106; end; hence thesis; end; hence thesis by Th33; end; theorem Th85: for th st th in ].0,PI/2.[ holds cos.th > 0 proof given th1 such that A1:th1 in ].0,PI/2.[ & cos.th1 <= 0; reconsider th1 as Real; cos is_continuous_on REAL by Th72,FDIFF_1:33; then A2:cos is_continuous_on [.0,th1 .] by FCONT_1:17; A3:0 < th1 by A1,JORDAN6:45; cos.th1 <= cos.0 by A1,Th33,AXIOMS:22; then A4:[.cos.0,cos.th1 .] \/ [.cos.th1,cos.0 .] = [.cos.th1,cos.0 .] by RCOMP_1:18; 0 in [.cos.th1,cos.0 .] by A1,Th33,TOPREAL5:1; then ex th2 be Real st th2 in [.0,th1 .] & cos.th2 = 0 by A2,A3,A4,FCONT_2:16; then consider th2 be Real such that A5:th2 in [.0,th1 .] & 0 < th1 & cos.th2 = 0 by A3; A6: 0 <= th2 & th2 <= th1 & th1 < PI/2 by A1,A5,JORDAN6:45,TOPREAL5:1; then A7: 0<th2 & th2<PI/2 by A5,Th33,AXIOMS:21,22; A8:PI/2/2 = PI/(2*2) by XCMPLX_1:79 .= PI/4; A9: 0/2<th2/2 & th2/2 < PI/2/2 by A7,REAL_1:73; PI in ].0, 4.[ by Def30; then 0< PI & PI < 4 by JORDAN6:45; then PI/4 < 4/4 by REAL_1:73; then A10: 0 < th2/2 & th2/2 < 1 by A8,A9,AXIOMS:22; 0 = cos.(th2/2*2) by A5,XCMPLX_1:88 .= cos.(th2/2 + th2/2) by XCMPLX_1:11 .= (cos.(th2/2)) * (cos.(th2/2)) -(sin.(th2/2)) * (sin.(th2/2)) by Th79 .= (cos.(th2/2))^2 - (sin.(th2/2)) * (sin.(th2/2)) by SQUARE_1:def 3 .= (cos.(th2/2))^2 - (sin.(th2/2))^2 by SQUARE_1:def 3 .= ((cos.(th2/2)) - (sin.(th2/2))) * ((cos.(th2/2)) + (sin.(th2/2))) by SQUARE_1:67; then cos.(th2/2) - sin.(th2/2) = 0 or cos.(th2/2) + sin.(th2/2) = 0 by XCMPLX_1:6; then A11: cos.(th2/2) = sin.(th2/2) or cos.(th2/2) = -sin.(th2/2) by XCMPLX_0:def 6,XCMPLX_1:15; A12: th2/2 in ].0,1 .[ by A10,JORDAN6:45; A13: ].0,1 .[ c= [.0,1 .] by RCOMP_1:15; then A14: cos.(th2/2) > 0 by A12,Th74; A15: sin.(th2/2) >= 0 by A12,A13,Lm23; (2*th2) in ].0,4.[ & (sin/cos).((2*th2)/4) = 1 proof A16: 4*0 < 4*(th2/2) & 4*(th2/2) < 4*1 by A10,Lm1; A17: 4*(th2/2) = 2*th2 & (2*th2)/4 = th2/2 proof thus 4*(th2/2) = (th2*4)/2 by XCMPLX_1:75 .= th2*(4/2) by XCMPLX_1:75 .= 2*th2; thus (2*th2)/4 = th2/(4/2) by XCMPLX_1:78 .= th2/2; end; hence (2*th2) in ].0,4.[ by A16,JORDAN6:45; (sin.(th2/2)) * (cos.(th2/2))"=1 by A11,A14,A15,REAL_1:26,50,XCMPLX_0:def 7 ; hence (sin/cos).((2*th2)/4) =1 by A12,A17,Th75,RFUNCT_1:def 4; end; then A18: 2*th2 =PI by Def30; th2 = th2*(2/2) .= PI/2 by A18,XCMPLX_1:75; hence contradiction by A6; end; theorem for th st th in ].0,PI/2.[ holds cos(th) > 0 proof let th such that A1: th in ].0,PI/2.[; cos(th)=cos.th by Def23; hence thesis by A1,Th85; end;