Answer:
Explanation:
At first, we should factorize the equation:
sin²θ+3sinθ=0
sinθ(sinθ+3)=0
Either sinθ=0 or sinθ+3=0:
If sinθ=0, then θ=0 or θ=180
If sinθ+3=0, then sinθ=-3. This is not possible, because the maximum value of sinθ is 1.
Therefore, the only solution is θ=0 or θ=180°.