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