-0.5*log(x^2 + 1) - atan(x)/x + log(x)
/ 2\ -2*atan(x) - x*log\1 + x / + 2*x*log(x) --------------------------------------- 2*x
/ / 2\ \ -2*atan(x) + x*\- log\1 + x / + 2*log(x)/ ----------------------------------------- 2*x
/ 2\ -2*atan(x) - x*log\1 + x / + 2*x*log(x) --------------------------------------- 2*x