z
------ + atan(z)
2
1 + z
$$\frac{z}{z^{2} + 1} + \operatorname{atan}{\left(z \right)}$$
/ 2 \
| z |
2*|1 - ------|
| 2|
\ 1 + z /
--------------
2
1 + z
$$\frac{2 \left(- \frac{z^{2}}{z^{2} + 1} + 1\right)}{z^{2} + 1}$$
/ 2 \
| 4*z |
2*z*|-4 + ------|
| 2|
\ 1 + z /
-----------------
2
/ 2\
\1 + z /
$$\frac{2 z \left(\frac{4 z^{2}}{z^{2} + 1} - 4\right)}{\left(z^{2} + 1\right)^{2}}$$