Primitive of Reciprocal of a x + b cubed/Proof 1

Theorem

 * $\displaystyle \int \frac {\mathrm d x} {\left({a x + b}\right)^3} = -\frac 1 {2 a \left({a x + b}\right)^2} + C$

Proof
Let $u = a x + b$.

Then: