let Z be open Subset of REAL ; :: thesis: ( Z c= ].(- 1),1.[ implies ( exp_R (#) (arctan + arccot ) is_differentiable_on Z & ( for x being Real st x in Z holds
((exp_R (#) (arctan + arccot )) `| Z) . x = (exp_R . x) * ((arctan . x) + (arccot . x)) ) ) )
assume A1:
Z c= ].(- 1),1.[
; :: thesis: ( exp_R (#) (arctan + arccot ) is_differentiable_on Z & ( for x being Real st x in Z holds
((exp_R (#) (arctan + arccot )) `| Z) . x = (exp_R . x) * ((arctan . x) + (arccot . x)) ) )
A3:
].(- 1),1.[ c= [.(- 1),1.]
by XXREAL_1:25;
then
].(- 1),1.[ c= dom arctan
by SIN_COS9:23, XBOOLE_1:1;
then A4:
Z c= dom arctan
by A1, XBOOLE_1:1;
].(- 1),1.[ c= dom arccot
by A3, SIN_COS9:24, XBOOLE_1:1;
then
Z c= dom arccot
by A1, XBOOLE_1:1;
then
Z c= (dom arctan ) /\ (dom arccot )
by A4, XBOOLE_1:19;
then A5:
Z c= dom (arctan + arccot )
by VALUED_1:def 1;
then
Z c= (dom exp_R ) /\ (dom (arctan + arccot ))
by TAYLOR_1:16, XBOOLE_1:19;
then A6:
Z c= dom (exp_R (#) (arctan + arccot ))
by VALUED_1:def 4;
A7:
exp_R is_differentiable_on Z
by TAYLOR_1:16, FDIFF_1:34;
A8:
( arctan + arccot is_differentiable_on Z & ( for x being Real st x in Z holds
((arctan + arccot ) `| Z) . x = 0 ) )
by A1, Th37;
for x being Real st x in Z holds
((exp_R (#) (arctan + arccot )) `| Z) . x = (exp_R . x) * ((arctan . x) + (arccot . x))
proof
let x be
Real;
:: thesis: ( x in Z implies ((exp_R (#) (arctan + arccot )) `| Z) . x = (exp_R . x) * ((arctan . x) + (arccot . x)) )
assume A9:
x in Z
;
:: thesis: ((exp_R (#) (arctan + arccot )) `| Z) . x = (exp_R . x) * ((arctan . x) + (arccot . x))
((exp_R (#) (arctan + arccot )) `| Z) . x =
(((arctan + arccot ) . x) * (diff exp_R ,x)) + ((exp_R . x) * (diff (arctan + arccot ),x))
by A6, A7, A8, A9, FDIFF_1:29
.=
(((arctan . x) + (arccot . x)) * (diff exp_R ,x)) + ((exp_R . x) * (diff (arctan + arccot ),x))
by A5, A9, VALUED_1:def 1
.=
(((arctan . x) + (arccot . x)) * (exp_R . x)) + ((exp_R . x) * (diff (arctan + arccot ),x))
by TAYLOR_1:16
.=
(((arctan . x) + (arccot . x)) * (exp_R . x)) + ((exp_R . x) * (((arctan + arccot ) `| Z) . x))
by A8, A9, FDIFF_1:def 8
.=
(((arctan . x) + (arccot . x)) * (exp_R . x)) + ((exp_R . x) * 0 )
by A1, A9, Th37
.=
(exp_R . x) * ((arctan . x) + (arccot . x))
;
hence
((exp_R (#) (arctan + arccot )) `| Z) . x = (exp_R . x) * ((arctan . x) + (arccot . x))
;
:: thesis: verum
end;
hence
( exp_R (#) (arctan + arccot ) is_differentiable_on Z & ( for x being Real st x in Z holds
((exp_R (#) (arctan + arccot )) `| Z) . x = (exp_R . x) * ((arctan . x) + (arccot . x)) ) )
by A6, A7, A8, FDIFF_1:29; :: thesis: verum