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