Primitive of Inverse Hyperbolic Tangent of x over a over x

Also see

 * Primitive of $\dfrac 1 x \arsinh \dfrac x a$


 * Primitive of $\dfrac 1 x \arcosh \dfrac x a$


 * Primitive of $\dfrac 1 x \arcoth \dfrac x a$


 * Primitive of $\dfrac 1 x \arsech \dfrac x a$


 * Primitive of $\dfrac 1 x \arcsch \dfrac x a$