Rates of Change in Polar Functions

For the bicycle pedal, $r = 17$ no matter what $\theta$ is: the pedal's distance from the crank center never changes, so its polar graph is a circle. Most polar curves are not like that. As $\theta$ increases, $r$ changes, and the point moves toward or away from the pole. This last note of Unit 3 asks two questions: which way is the point moving, and how fast is $r$ changing?