$$\frac{1}{- x^{2} + 1}$$
2*x
----------
2
/ 2\
\-1 + x /
$$\frac{2 x}{\left(x^{2} - 1\right)^{2}}$$
/ 2 \
| 4*x |
2*|1 - -------|
| 2|
\ -1 + x /
---------------
2
/ 2\
\-1 + x /
$$\frac{1}{\left(x^{2} - 1\right)^{2}} \left(- \frac{8 x^{2}}{x^{2} - 1} + 2\right)$$