Primitive of Cosine of a x over x

Proof
The validity of $(1)$ follows from Cosine Function is Absolutely Convergent.

Also see

 * Primitive of $\dfrac {\sin a x} x$


 * Primitive of $\dfrac {\tan a x} x$


 * Primitive of $\dfrac {\cot a x} x$


 * Primitive of $\dfrac {\sec a x} x$


 * Primitive of $\dfrac {\csc a x} x$