Primitive of Power of Hyperbolic Cosine of a x

Theorem

 * $\displaystyle \int \cosh^n a x \ \mathrm d x = \frac {\cosh^{n - 1} a x \sinh a x} {a n} + \frac {n - 1} n \int \cosh^{n - 2} a x \ \mathrm d x + C$

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

let:

and let:

Then:

Also see

 * Primitive of $\sinh^n a x$
 * Primitive of $\tanh^n a x$
 * Primitive of $\coth^n a x$
 * Primitive of $\operatorname{sech}^n a x$
 * Primitive of $\operatorname{csch}^n a x$