16*acot(x)
d --(16*acot(x)) dx
-16 ------ 2 1 + x
32*x --------- 2 / 2\ \1 + x /
/ 2 \ | 4*x | -32*|-1 + ------| | 2| \ 1 + x / ----------------- 2 / 2\ \1 + x /