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