Answer
$(2, -\frac{\pi}{2})$, $(-2, \frac{\pi}{2})$
Work Step by Step
1. Given $(0,-2)$ (on $-y$ axis) in rectangular coordinates, we have $r=\sqrt {0+4}=2$ and $\theta=-\frac{\pi}{2}$, thus we have $(2, -\frac{\pi}{2})$ in polar coordinates for $r\gt0$.
2. For $r\lt0$, we can choose $(-2, \frac{\pi}{2})$ for the same point.
