Explain in one or two complete sentences why points on a polar curve where (or is…

MATHEMATICS · Subjective · AP · Calculus BC · Parametric, Polar, and Vector-Valued Functions · Parametric, Polar, and Vector-Valued Functions

Problem

Explain in one or two complete sentences why points on a polar curve

r=f(\theta)

where

\displaystyle \frac{dr}{d\theta}=0

(or is undefined) are considered candidates for local maximum or minimum radial distance from the origin.