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

Lemma for Primitive of Reciprocal of $\paren {p + q \sin a x}^2$
The Weierstrass Substitution for $\ds \int \frac {\d x} {\paren {p + q \sin a x}^2}$ yields:
 * $\ds \frac 2 a \int \frac {\paren {u^2 + 1} \rd u} {\paren {p u^2 + 2 q u + p}^2}$

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