Primitive of Cube of Hyperbolic Tangent of a x

Theorem

 * $\ds \int \tanh^3 a x \rd x = \frac {\ln \size {\cosh a x} } a - \frac {\tanh^2 a x} {2 a} + C$

Also see

 * Primitive of $\coth^3 a x$
 * Primitive of $\sech^3 a x$
 * Primitive of $\csch^3 a x$