Answer
Counterexample: $\displaystyle \theta=\frac{\pi}{2}$
(sample answer)
Work Step by Step
The idea here is:
"Generate a zero in the denominator of the RHS,
so it's not defined, while the LHS is."
We can do this with, say, $\displaystyle \theta=\frac{\pi}{2}.$
LHS=1
RHS is not defined
LHS$\neq$RHS so the identity is not valid.