# How do you find the exact value of  Arctan (-sqrt3/3)?

$\text{arctan} \left(- \frac{\sqrt{3}}{3}\right) = \textcolor{g r e e n}{- \frac{\pi}{6}} = \textcolor{g r e e n}{- {30}^{\circ}}$
Note that $\frac{\sqrt{3}}{3} = \frac{1}{\sqrt{3}}$
Assuming the standard restriction of $\text{arctan} \in \left[- \frac{\pi}{2} , + \frac{\pi}{2}\right]$