let r be Real; ( 0 < r implies ex M, L being Real st
( 0 <= M & 0 <= L & ( for n being Nat
for x, s being Real st x in ].(- r),r.[ & 0 < s & s < 1 holds
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !) ) ) )
assume A1:
r > 0
; ex M, L being Real st
( 0 <= M & 0 <= L & ( for n being Nat
for x, s being Real st x in ].(- r),r.[ & 0 < s & s < 1 holds
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !) ) )
take M = exp_R . r; ex L being Real st
( 0 <= M & 0 <= L & ( for n being Nat
for x, s being Real st x in ].(- r),r.[ & 0 < s & s < 1 holds
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !) ) )
take L = r; ( 0 <= M & 0 <= L & ( for n being Nat
for x, s being Real st x in ].(- r),r.[ & 0 < s & s < 1 holds
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !) ) )
now for n being Nat
for x, s being Real st x in ].(- r),r.[ & 0 < s & s < 1 holds
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !)let n be
Nat;
for x, s being Real st x in ].(- r),r.[ & 0 < s & s < 1 holds
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !)now for x, s being Real st x in ].(- r),r.[ & 0 < s & s < 1 holds
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !)A2:
for
a,
b being
Real st
0 <= a &
a <= b holds
for
n being
Nat holds
(
0 <= a |^ n &
a |^ n <= b |^ n )
let x,
s be
Real;
( x in ].(- r),r.[ & 0 < s & s < 1 implies |.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !) )assume that A8:
x in ].(- r),r.[
and A9:
0 < s
and A10:
s < 1
;
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !)
x in ].(0 - r),(0 + r).[
by A8;
then A11:
|.(x - 0).| < r
by RCOMP_1:1;
|.x.| >= 0
by COMPLEX1:46;
then A12:
|.x.| |^ n <= L |^ n
by A11, A2;
|.x.| >= 0
by COMPLEX1:46;
then
s * |.x.| < 1
* r
by A9, A10, A11, XREAL_1:97;
then
|.s.| * |.x.| < r
by A9, ABSVALUE:def 1;
then
|.((s * x) - 0).| < r
by COMPLEX1:65;
then A13:
s * x in ].(0 - r),(0 + r).[
by RCOMP_1:1;
then A14:
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| =
|.(((exp_R . (s * x)) * (x |^ n)) / (n !)).|
by Th7
.=
|.((exp_R . (s * x)) * ((x |^ n) / (n !))).|
by XCMPLX_1:74
.=
|.(exp_R . (s * x)).| * |.((x |^ n) / (n !)).|
by COMPLEX1:65
;
exp_R . (s * x) >= 0
by SIN_COS:54;
then A15:
(
r in ([#] REAL) /\ (dom exp_R) &
|.(exp_R . (s * x)).| = exp_R . (s * x) )
by ABSVALUE:def 1, TAYLOR_1:16, XREAL_0:def 1;
for
x0 being
Real holds
0 <= diff (
exp_R,
x0)
by TAYLOR_1:16;
then A16:
exp_R | ([#] REAL) is
non-decreasing
by FDIFF_2:39, TAYLOR_1:16;
|.((x |^ n) / (n !)).| =
|.(x |^ n).| / |.(n !).|
by COMPLEX1:67
.=
|.(x |^ n).| / (n !)
by ABSVALUE:def 1
.=
(|.x.| |^ n) / (n !)
by Th1
;
then A17:
|.((x |^ n) / (n !)).| <= (L |^ n) / (n !)
by A12, XREAL_1:72;
A18:
(
|.(exp_R . (s * x)).| >= 0 &
|.((x |^ n) / (n !)).| >= 0 )
by COMPLEX1:46;
s * x in { p where p is Real : ( - r < p & p < r ) }
by A13, RCOMP_1:def 2;
then consider g being
Real such that A19:
(
g = s * x &
- r < g &
g < r )
;
reconsider g =
g as
Element of
REAL by XREAL_0:def 1;
(
g = s * x &
- r < g &
g < r )
by A19;
then
|.(exp_R . (s * x)).| <= M
by A16, A15, RFUNCT_2:24, TAYLOR_1:16;
then
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= M * ((L |^ n) / (n !))
by A18, A17, A14, XREAL_1:66;
hence
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !)
by XCMPLX_1:74;
verum end; hence
for
x,
s being
Real st
x in ].(- r),r.[ &
0 < s &
s < 1 holds
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !)
;
verum end;
hence
( 0 <= M & 0 <= L & ( for n being Nat
for x, s being Real st x in ].(- r),r.[ & 0 < s & s < 1 holds
|.(((((diff (exp_R,].(- r),r.[)) . n) . (s * x)) * (x |^ n)) / (n !)).| <= (M * (L |^ n)) / (n !) ) )
by A1, SIN_COS:54; verum