Primitive of Product of Cosecant and Cotangent

Theorem

 * $\displaystyle \int \csc x \cot x \rd x = -\csc x + C$

where $C$ is an arbitrary constant.

Proof
From Derivative of Cosecant Function:
 * $\dfrac \d {\d x} \csc x = -\csc x \cot x$

The result follows from the definition of primitive.