Answer
($\frac{-1}{2}$, $\frac{\sqrt 3}{2}$)
Work Step by Step
If you look at the unit circle you cannot locate $\frac{-4\pi}{3}$. You have to add 2$\pi$, a full unit circle rotation, to it. You end up with $\frac{2\pi}{3}$, which is coterminal to $\frac{-4\pi}{3}$ and is between 0 and 2$\pi$. Look at the unit circle and trace its corresponding terminal point.
