$$\frac{a}{a^{2} x^{2} + 1}$$
3
-2*x*a
------------
2
/ 2 2\
\1 + a *x /
$$- \frac{2 a^{3} x}{\left(a^{2} x^{2} + 1\right)^{2}}$$
/ 2 2 \
3 | 4*a *x |
2*a *|-1 + ---------|
| 2 2|
\ 1 + a *x /
---------------------
2
/ 2 2\
\1 + a *x /
$$\frac{2 a^{3}}{\left(a^{2} x^{2} + 1\right)^{2}} \left(\frac{4 a^{2} x^{2}}{a^{2} x^{2} + 1} - 1\right)$$