2 4*acot (x)*(3 + 2*x*acot(x)) ---------------------------- 2 / 2\ \1 + x /
/ 2 2 \ | 2 3 9*x*acot(x) 4*x *acot (x)| 8*|acot (x) - ------ - ----------- - -------------|*acot(x) | 2 2 2 | \ 1 + x 1 + x 1 + x / ----------------------------------------------------------- 2 / 2\ \1 + x /