Answer
See explanations.
Work Step by Step
Multiply the left side numerator and the denominator by $sin(v)$ and use the relation $csc(v)=\frac{1}{sin(v)}$. We have $LHS=\frac{sin(v)csc(v)-sin(v)}{sin(v)csc(v)+sin(v)}=\frac{1-sin(v)}{1+sin(v)}=RHS$