$$\frac{2}{\frac{x^{2}}{4} + 1}$$
-x
---------
2
/ 2\
| x |
|1 + --|
\ 4 /
$$- \frac{x}{\left(\frac{x^{2}}{4} + 1\right)^{2}}$$
/ 2 \
| 4*x |
16*|-1 + ------|
| 2|
\ 4 + x /
----------------
2
/ 2\
\4 + x /
$$\frac{\frac{64 x^{2}}{x^{2} + 4} - 16}{\left(x^{2} + 4\right)^{2}}$$