/ 2 \ \9*x + 1/*acot(3*x)
(9*x^2 + 1)*acot(3*x)
/ 2 \ 3*\9*x + 1/ - ------------ + 18*x*acot(3*x) 2 1 + 9*x
/ 3*x \ 18*|- -------- + acot(3*x)| | 2 | \ 1 + 9*x /
/ 2 \ | 18*x | 54*|-2 + --------| | 2| \ 1 + 9*x / ------------------ 2 1 + 9*x