Answer
$-2 \csc (\frac{v-\pi}{2})+C$
Work Step by Step
Let u=$\csc (\frac{v-\pi}{2})=>\frac{-1}{2} \csc(\frac{v-\pi}{2})\cot (\frac{v-\pi}{2})dv$
$=>-2du=\csc(\frac{v-\pi}{2}) \cot(\frac{v-\pi}{2})dv$
=$\csc(\frac{v-\pi}{2}) \cot(\frac{v-\pi}{2})$
=$\int -2du$
=$-2u+C$
=$-2 \csc (\frac{v-\pi}{2})+C$