let a be Real; :: thesis: for Z being open Subset of REAL
for f being PartFunc of REAL ,REAL st Z c= dom ((#R (3 / 2)) * f) & ( for x being Real st x in Z holds
( f . x = a + x & f . x > 0 ) ) holds
( (#R (3 / 2)) * f is_differentiable_on Z & ( for x being Real st x in Z holds
(((#R (3 / 2)) * f) `| Z) . x = (3 / 2) * ((a + x) #R (1 / 2)) ) )
let Z be open Subset of REAL ; :: thesis: for f being PartFunc of REAL ,REAL st Z c= dom ((#R (3 / 2)) * f) & ( for x being Real st x in Z holds
( f . x = a + x & f . x > 0 ) ) holds
( (#R (3 / 2)) * f is_differentiable_on Z & ( for x being Real st x in Z holds
(((#R (3 / 2)) * f) `| Z) . x = (3 / 2) * ((a + x) #R (1 / 2)) ) )
let f be PartFunc of REAL ,REAL ; :: thesis: ( Z c= dom ((#R (3 / 2)) * f) & ( for x being Real st x in Z holds
( f . x = a + x & f . x > 0 ) ) implies ( (#R (3 / 2)) * f is_differentiable_on Z & ( for x being Real st x in Z holds
(((#R (3 / 2)) * f) `| Z) . x = (3 / 2) * ((a + x) #R (1 / 2)) ) ) )
assume A1:
( Z c= dom ((#R (3 / 2)) * f) & ( for x being Real st x in Z holds
( f . x = a + x & f . x > 0 ) ) )
; :: thesis: ( (#R (3 / 2)) * f is_differentiable_on Z & ( for x being Real st x in Z holds
(((#R (3 / 2)) * f) `| Z) . x = (3 / 2) * ((a + x) #R (1 / 2)) ) )
then
for y being set st y in Z holds
y in dom f
by FUNCT_1:21;
then A2:
Z c= dom f
by TARSKI:def 3;
A3:
for x being Real st x in Z holds
f . x = (1 * x) + a
by A1;
then A4:
( f is_differentiable_on Z & ( for x being Real st x in Z holds
(f `| Z) . x = 1 ) )
by A2, FDIFF_1:31;
A5:
for x being Real st x in Z holds
(#R (3 / 2)) * f is_differentiable_in x
then A8:
(#R (3 / 2)) * f is_differentiable_on Z
by A1, FDIFF_1:16;
for x being Real st x in Z holds
(((#R (3 / 2)) * f) `| Z) . x = (3 / 2) * ((a + x) #R (1 / 2))
proof
let x be
Real;
:: thesis: ( x in Z implies (((#R (3 / 2)) * f) `| Z) . x = (3 / 2) * ((a + x) #R (1 / 2)) )
assume A9:
x in Z
;
:: thesis: (((#R (3 / 2)) * f) `| Z) . x = (3 / 2) * ((a + x) #R (1 / 2))
then A10:
f is_differentiable_in x
by A4, FDIFF_1:16;
A11:
(
f . x = a + x &
f . x > 0 )
by A1, A9;
then diff ((#R (3 / 2)) * f),
x =
((3 / 2) * ((f . x) #R ((3 / 2) - 1))) * (diff f,x)
by A10, TAYLOR_1:22
.=
((3 / 2) * ((f . x) #R ((3 / 2) - 1))) * ((f `| Z) . x)
by A4, A9, FDIFF_1:def 8
.=
((3 / 2) * ((a + x) #R ((3 / 2) - 1))) * 1
by A2, A3, A9, A11, FDIFF_1:31
.=
(3 / 2) * ((a + x) #R (1 / 2))
;
hence
(((#R (3 / 2)) * f) `| Z) . x = (3 / 2) * ((a + x) #R (1 / 2))
by A8, A9, FDIFF_1:def 8;
:: thesis: verum
end;
hence
( (#R (3 / 2)) * f is_differentiable_on Z & ( for x being Real st x in Z holds
(((#R (3 / 2)) * f) `| Z) . x = (3 / 2) * ((a + x) #R (1 / 2)) ) )
by A1, A5, FDIFF_1:16; :: thesis: verum