Primitive of Cube of Secant of a x

Theorem

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

Also see

 * Primitive of $\csc^3 a x$