Primitive of Tangent of a x/Examples/2 x

Example of Use of Primitive of $\tan a x$

 * $\ds \int \tan 3 x \rd x = \frac 1 2 \ln \size {\sec 2 x} + C$

Proof
From Primitive of $\tan a x$: Secant Form:

The result follows by setting $a = 2$.

Proof

 * : $\text {II}$. Calculus: Exercises $\text {XIV}$: $2$.