### I. Plotting points in the Polar Coordinate System

The point (2, π/3) lies at the intersection of a circle with radius 2, and the terminal side of the angle π/3:

Plot these: 1. (1, 3π/4), 2. (3, 210°)

Unlike the rectangular coordinate system, a point in the polar coordinate system can have multiple representations:

(r, θ) = (r, θ ± 2πn), n is an integer

Thus, (2, π/3) = (2, 7π/3) = (2, −5π/3) = …

If r < 0, find the ray that forms the angle with the polar axis and go in the opposite direction from the ray. For ex, (−2, π/3):

Thus (−2, π/3) = (2, 4π/3)

(−r, θ) = (r, θ ± π)