Answer
$\frac{4\pi}{3}, \frac{5\pi}{3}$
Work Step by Step
$4sin\theta+3\sqrt 3=\sqrt 3$,
$sin\theta=-\frac{\sqrt 3}{2}$,
$\theta=2k\pi+\frac{4\pi}{3}$ or $2k\pi+\frac{5\pi}{3}$ (k is an integer),
$\theta=\frac{4\pi}{3}, \frac{5\pi}{3}$ in $[0,2\pi)$.
