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