Question:

The number of solutions of $2\sin^2 x+3\sin x-2=0$ in $[0,2\pi]$ is

one

two

three

four

Step-by-Step Solution

Key Concept: Factor: $(2\sin x-1)(\sin x+2)=0$; $\sin x=1/2$ or $\sin x=-2$ (rejected)

Two solutions.

Correct Answer: 4