Primitive of Reciprocal of Power of x by Power of Power of x minus Power of a

Theorem

 * $\ds \int \frac {\d x} {x^m \ \paren {x^n - a^n}^r} = \frac 1 {a^n} \int \frac {\d x} {x^{m - n} \paren {x^n - a^n}^r} - \frac 1 {a^n} \int \frac {\d x} {x^m \paren {x^n - a^n}^{r - 1} }$