Answer
$\frac{\pi}{2},\frac{3\pi}{2}$
Work Step by Step
1. $sin^2\theta-1=0 \Longrightarrow sin\theta=\pm1$,
2. $sin\theta=1 \Longrightarrow \theta=\frac{\pi}{2}$ in $[0,2\pi)$,
3. $sin\theta=-1 \Longrightarrow \theta=\frac{3\pi}{2}$ in $[0,2\pi)$.
