Primitive of Inverse Hyperbolic Tangent of x over a over x

Also see

 * Primitive of $\dfrac 1 x \sinh^{-1} \dfrac x a$


 * Primitive of $\dfrac 1 x \cosh^{-1} \dfrac x a$


 * Primitive of $\dfrac 1 x \coth^{-1} \dfrac x a$


 * Primitive of $\dfrac 1 x \sech^{-1} \dfrac x a$


 * Primitive of $\dfrac 1 x \csch^{-1} \dfrac x a$