Answer
$$y=\frac{\pi}{3}$$
Work Step by Step
$$y=\tan^{-1}\sqrt3$$
*Remember: $\tan^{-1}A=x$ means that $\tan x=A$
Therefore, to find $y$, we need to recall which value of $y$ would have $\tan y=\sqrt3$.
$\tan y\gt0$ shows that we can find a value of $y$ in either quadrant I or III of the unit circle. The choice is arbitrary. I would choose quadrant I here.
In quadrant I, $\frac{\pi}{3}$ is the value of the angle with which $\tan(\frac{\pi}{3})=\sqrt3$
Therefore, $$y=\frac{\pi}{3}$$