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