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