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