Primitive of x by Inverse Hyperbolic Cosine of x over a

Theorem

 * $\displaystyle \int x \cosh^{-1} \frac x a \rd x = \begin{cases}

\paren {\dfrac {x^2} 2 - \dfrac {a^2} 4} \cosh^{-1} \dfrac x a - \dfrac {x \sqrt {x^2 - a^2} } 4 + C & : \cosh^{-1} \dfrac x a > 0 \\ \paren {\dfrac {x^2} 2 - \dfrac {a^2} 4} \cosh^{-1} \dfrac x a + \dfrac {x \sqrt {x^2 - a^2} } 4 + C & : \cosh^{-1} \dfrac x a < 0 \end{cases}$

Proof
With a view to expressing the primitive in the form:
 * $\displaystyle \int u \frac {\d v} {\d x} \rd x = u v - \int v \frac {\d u} {\d x} \rd x$

let:

and let:

Then:

Also see

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


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


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


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


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