Fundamentals and Basic Identities

Remember that ${\displaystyle {\sin }^2<!--\; \; -->x+{\cos }^2<!--\; \; -->x=1}$. We can rearrange this to simplify our given equation:

${\displaystyle \frac{{\cos }^2<!--\; \; -->x-<!--\; -\; -->1}{\sin <!--\; \; -->x}}$

${\displaystyle =\frac{-<!--\; -\; -->{\sin }^2<!--\; \; -->x}{\sin <!--\; \; -->x}=-<!--\; -\; -->\sin <!--\; \; -->x}$