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