Answer
$\frac{2\pi}{3},\frac{5\pi}{3}$
Work Step by Step
$\sqrt 3 cot\theta+1=0$,
$cot\theta=-\frac{\sqrt 3}{3}$
$\theta=k\pi+\frac{2\pi}{3}$ (k is an integer),
$\theta=\frac{2\pi}{3},\frac{5\pi}{3}$ in $[0,2\pi)$.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.