let a be Real; :: thesis: for Z being open Subset of REAL
for f being PartFunc of REAL ,REAL st Z c= dom ((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) & ( for x being Real st x in Z holds
f . x = x * (log number_e ,a) ) & a > 0 & a <> number_e holds
( (1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f)) is_differentiable_on Z & ( for x being Real st x in Z holds
(((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) `| Z) . x = (exp_R . x) / (a #R x) ) )
let Z be open Subset of REAL ; :: thesis: for f being PartFunc of REAL ,REAL st Z c= dom ((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) & ( for x being Real st x in Z holds
f . x = x * (log number_e ,a) ) & a > 0 & a <> number_e holds
( (1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f)) is_differentiable_on Z & ( for x being Real st x in Z holds
(((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) `| Z) . x = (exp_R . x) / (a #R x) ) )
let f be PartFunc of REAL ,REAL ; :: thesis: ( Z c= dom ((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) & ( for x being Real st x in Z holds
f . x = x * (log number_e ,a) ) & a > 0 & a <> number_e implies ( (1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f)) is_differentiable_on Z & ( for x being Real st x in Z holds
(((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) `| Z) . x = (exp_R . x) / (a #R x) ) ) )
assume that
A1:
Z c= dom ((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f)))
and
A2:
( ( for x being Real st x in Z holds
f . x = x * (log number_e ,a) ) & a > 0 )
and
A3:
a <> number_e
; :: thesis: ( (1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f)) is_differentiable_on Z & ( for x being Real st x in Z holds
(((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) `| Z) . x = (exp_R . x) / (a #R x) ) )
Z c= dom (exp_R / (exp_R * f))
by A1, VALUED_1:def 5;
then
Z c= (dom exp_R ) /\ ((dom (exp_R * f)) \ ((exp_R * f) " {0 }))
by RFUNCT_1:def 4;
then A4:
Z c= dom (exp_R * f)
by XBOOLE_1:1;
A5:
exp_R is_differentiable_on Z
by FDIFF_1:34, TAYLOR_1:16;
A6:
( exp_R * f is_differentiable_on Z & ( for x being Real st x in Z holds
((exp_R * f) `| Z) . x = (a #R x) * (log number_e ,a) ) )
by A2, A4, Th11;
A7:
for x being Real st x in Z holds
(exp_R * f) . x <> 0
then A8:
exp_R / (exp_R * f) is_differentiable_on Z
by A5, A6, FDIFF_2:21;
A9:
1 - (log number_e ,a) <> 0
for x being Real st x in Z holds
(((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) `| Z) . x = (exp_R . x) / (a #R x)
proof
let x be
Real;
:: thesis: ( x in Z implies (((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) `| Z) . x = (exp_R . x) / (a #R x) )
assume A12:
x in Z
;
:: thesis: (((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) `| Z) . x = (exp_R . x) / (a #R x)
then A13:
(exp_R * f) . x =
exp_R . (f . x)
by A4, FUNCT_1:22
.=
exp_R . (x * (log number_e ,a))
by A2, A12
.=
a #R x
by A2, Th1
;
A14:
a #R x > 0
by A2, PREPOWER:95;
A15:
exp_R is_differentiable_in x
by SIN_COS:70;
A16:
exp_R * f is_differentiable_in x
by A6, A12, FDIFF_1:16;
A17:
(exp_R * f) . x <> 0
by A7, A12;
(((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) `| Z) . x =
(1 / (1 - (log number_e ,a))) * (diff (exp_R / (exp_R * f)),x)
by A1, A8, A12, FDIFF_1:28
.=
(1 / (1 - (log number_e ,a))) * ((((diff exp_R ,x) * ((exp_R * f) . x)) - ((diff (exp_R * f),x) * (exp_R . x))) / (((exp_R * f) . x) ^2 ))
by A15, A16, A17, FDIFF_2:14
.=
(1 / (1 - (log number_e ,a))) * ((((exp_R . x) * (a #R x)) - ((diff (exp_R * f),x) * (exp_R . x))) / ((a #R x) ^2 ))
by A13, SIN_COS:70
.=
(1 / (1 - (log number_e ,a))) * (((exp_R . x) * ((a #R x) - (diff (exp_R * f),x))) / ((a #R x) ^2 ))
.=
(1 / (1 - (log number_e ,a))) * (((exp_R . x) * ((a #R x) - (((exp_R * f) `| Z) . x))) / ((a #R x) ^2 ))
by A6, A12, FDIFF_1:def 8
.=
(1 / (1 - (log number_e ,a))) * (((exp_R . x) * ((a #R x) - ((a #R x) * (log number_e ,a)))) / ((a #R x) ^2 ))
by A2, A4, A12, Th11
.=
((1 / (1 - (log number_e ,a))) * (((1 - (log number_e ,a)) * (exp_R . x)) * (a #R x))) / ((a #R x) ^2 )
by XCMPLX_1:75
.=
((((1 / (1 - (log number_e ,a))) * (1 - (log number_e ,a))) * (exp_R . x)) * (a #R x)) / ((a #R x) ^2 )
.=
((1 * (exp_R . x)) * (a #R x)) / ((a #R x) ^2 )
by A9, XCMPLX_1:107
.=
(exp_R . x) / (a #R x)
by A14, XCMPLX_1:92
;
hence
(((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) `| Z) . x = (exp_R . x) / (a #R x)
;
:: thesis: verum
end;
hence
( (1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f)) is_differentiable_on Z & ( for x being Real st x in Z holds
(((1 / (1 - (log number_e ,a))) (#) (exp_R / (exp_R * f))) `| Z) . x = (exp_R . x) / (a #R x) ) )
by A1, A8, FDIFF_1:28; :: thesis: verum