Primitive of Square of Hyperbolic Secant of a x over Hyperbolic Tangent of a x

Theorem

 * $\displaystyle \int \frac {\operatorname{sech}^2 a x \ \mathrm d x} {\tanh a x} = \frac 1 a \ln \left\vert{\tanh a x}\right\vert + C$