(3, 30°)
1. You may add or subtract any multiple of 360°
to the angle q and get a new
pair of polar coordinates for the same point.
(3, 390°), (3, -330°), etc.
2. Or you may multiply the radius r, in this case 3,
by -1 and add or subtract any ODD multiple of 180° and
get a new pair of polar coordinates for the same point
(-3,210°), (-3,-150°), etc.
Edwin