A1:
|.(0 - 0).| = 0
by ABSVALUE:2;
let r, x be Real; ( 0 < r implies ( Maclaurin (exp_R,].(- r),r.[,x) = x rExpSeq & Maclaurin (exp_R,].(- r),r.[,x) is absolutely_summable & exp_R . x = Sum (Maclaurin (exp_R,].(- r),r.[,x)) ) )
assume
r > 0
; ( Maclaurin (exp_R,].(- r),r.[,x) = x rExpSeq & Maclaurin (exp_R,].(- r),r.[,x) is absolutely_summable & exp_R . x = Sum (Maclaurin (exp_R,].(- r),r.[,x)) )
then
0 in ].(0 - r),(0 + r).[
by A1, RCOMP_1:1;
then A2:
0 in dom (exp_R | ].(- r),r.[)
by Th5;
now for t being object st t in NAT holds
(Maclaurin (exp_R,].(- r),r.[,x)) . t = (x rExpSeq) . tlet t be
object ;
( t in NAT implies (Maclaurin (exp_R,].(- r),r.[,x)) . t = (x rExpSeq) . t )assume
t in NAT
;
(Maclaurin (exp_R,].(- r),r.[,x)) . t = (x rExpSeq) . tthen reconsider n =
t as
Element of
NAT ;
thus (Maclaurin (exp_R,].(- r),r.[,x)) . t =
((((diff (exp_R,].(- r),r.[)) . n) . 0) * ((x - 0) |^ n)) / (n !)
by TAYLOR_1:def 7
.=
(((exp_R | ].(- r),r.[) . 0) * (x |^ n)) / (n !)
by Th6
.=
((exp_R . 0) * (x |^ n)) / (n !)
by A2, FUNCT_1:47
.=
(x rExpSeq) . t
by SIN_COS:def 5, SIN_COS2:13
;
verum end;
then
Maclaurin (exp_R,].(- r),r.[,x) = x rExpSeq
by FUNCT_2:12;
hence
( Maclaurin (exp_R,].(- r),r.[,x) = x rExpSeq & Maclaurin (exp_R,].(- r),r.[,x) is absolutely_summable & exp_R . x = Sum (Maclaurin (exp_R,].(- r),r.[,x)) )
by Th15, SIN_COS:def 22; verum