Primitive of Reciprocal of p plus q by Sine of a x/Weierstrass Substitution

Lemma for Primitive of Reciprocal of $p + q \sin a x$
The Weierstrass Substitution of $\ds \int \frac {\d x} {p + q \sin a x}$ is:
 * $\ds \frac 2 a \int \frac {\d u} {p u^2 + 2 q u + p}$

where $u = \tan \dfrac {a x} 2$.