Start by finding *r* at the endpoints. When *θ* = 0,
*r *= cos(0) = 1.
When , As *θ* moves from 0 to , the value of *r* = cos θ decreases from 1 to 0.
When *θ* = π, *r* = cos π = -1. Remembering how we graph polar coordinates with negative *r*, we find these points: When *θ* is in the second quadrant and *r* is negative, the point (*r*, *θ*) is in the fourth quadrant. As *θ* moves closer to π, the points (*r*, *θ*) move closer to the positive *x*-axis. As θ moves from to π, the value *r* = cos* θ* goes from 0 to -1. The points (*r*, *θ*) move further from the origin as *θ* gets closer to π. |