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