Question

How do you plot the point `(-3, -pi/2)`?

Answer 1

`(r,theta)=(-3,-pi/2)` will be a point on the positive Y-axis, `3` units above the origin.
(see below)

Explanation:

A graph showing the point `color(green)((r,theta)=(-3,-pi/2))`
and (hopefully) indicating it's derivation:

The angle of `-pi/2` is measured clockwise (since it is negative) from the X-axis.
A radius of `-3` is measured along the radial arm in the opposite direction (since it is negative) from the normal direction of the radial arm.