Solve for angles, A: $2\sin^2A+3\sin A-2=0$. Given:
$$y=2\sin^2A+3\sin A-2$$
Find all possible angles A. 
Where $0\le A \le 450$ when $y=0$.
We start with, $x=\sin A$
$$2x^2+3x-2=0\tag1$$
$$(2x-1)(x+2)=0\tag2$$
$\sin A={1\over 2}$ then $A=30^{0}$
I am stuck at this point. How can I find other angles of A?

Remember $\sin(x)$ is a periodic function with period $T=2\pi$.
