Primitive of Square of Sine of a x over Cosine of a x

Theorem

 * $\displaystyle \int \frac {\sin^2 a x \ \mathrm d x} {\cos a x} = \frac {-\sin a x} a + \frac 1 a \ln \left\vert{\tan \left({\frac \pi 4 + \frac {a x} 2}\right)}\right\vert + C$

Also see

 * Primitive of $\dfrac {\cos^2 a x} {\sin a x}$