Answer
See image:
Work Step by Step
Conversion formulas: $\left\{\begin{array}{ll}
(x,y)=(r\cos\theta,r\sin\theta) & \\
r^{2}=x^{2}+y^{2}, & \tan\theta=\frac{y}{x}
\end{array}\right.$
The points $(r,\theta)$ of the region are such that:
The angle $\pi/2$ terminates on the +y axis (Cartesian)
defines a line through the pole (the origin).
Since only nonnegative $r$'s are considered, only the points on the +y-axis are represented.
