Primitive of Square of Hyperbolic Cosine of a x over Hyperbolic Sine of a x

Theorem

 * $\ds \int \frac {\cosh^2 a x \rd x} {\sinh a x} = \frac {\cosh a x} a + \frac 1 a \ln \size {\tanh \frac {a x} 2} + C$