theorem :: FDIFF_11:53

for Z being open Subset of REAL st Z c= ].(- 1),1.[ holds
( (arctan + arccot) / exp_R is_differentiable_on Z & ( for x being Real st x in Z holds
(((arctan + arccot) / exp_R) `| Z) . x = - (((arctan . x) + (arccot . x)) / (exp_R . x)) ) )