/ 2\ \1 + x /*acot(x)
(1 + x^2)*acot(x)
-1 + 2*x*acot(x)
/ x \ 2*|- ------ + acot(x)| | 2 | \ 1 + x /
/ 2 \ | 2*x | 2*|-2 + ------| | 2| \ 1 + x / --------------- 2 1 + x