/ 2\ log\1 + x / x*atan(x) + ----------- 2
x*atan(x) + log(1 + x^2)/2
2*x ------ + atan(x) 2 1 + x
2 4*x 3 - ------ 2 1 + x ---------- 2 1 + x
/ 2 \ | 8*x | 2*x*|-7 + ------| | 2| \ 1 + x / ----------------- 2 / 2\ \1 + x /