Primitive of Cube of Hyperbolic Tangent of a x

Theorem

 * $\displaystyle \int \tanh^3 a x \ \mathrm d x = \frac {\ln \left\vert{\cosh a x}\right\vert} a - \frac {\tanh^2 a x} {2 a} + C$

Also see

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