Primitive of Cube of Tangent of a x

Theorem

 * $\displaystyle \int \tan^3 a x \ \mathrm d x = \frac {\tan^2 a x} {2 a} + \frac 1 a \ln \left\vert{\cos a x}\right\vert + C$

Also see

 * Primitive of $\cot^3 a x$