Answer
Graph:
.
Work Step by Step
Plotting points $(r,\theta)$,
$r$ is the directed distance of the point from the pole.
$\theta$ defines the angle of the ray on which the point lies,
- remains $\theta$ when $r$ is positive
- becomes $\theta\pm\pi$ when $r$ is negative
The region is such that:
the angle $\pi/2$ terminates on the +y axis (Cartesian), and defines a line through the pole (the origin) with slope $\tan( \pi/2) =$undefined (the y-axis).
Since only negative $r$'s are considered, only the points on the -y-axis are represented.
