Primitive of Reciprocal of Hyperbolic Sine of a x by Square of Hyperbolic Cosine of a x

Theorem

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