$$1 - \frac{5}{x^{2} + 1}$$
10*x
---------
2
/ 2\
\1 + x /
$$\frac{10 x}{\left(x^{2} + 1\right)^{2}}$$
/ 2 \
| 4*x |
10*|1 - ------|
| 2|
\ 1 + x /
---------------
2
/ 2\
\1 + x /
$$\frac{1}{\left(x^{2} + 1\right)^{2}} \left(- \frac{40 x^{2}}{x^{2} + 1} + 10\right)$$