Chapter 12 - Parametric Equations, Polar Coordinates, and Conic Sections - 12.3 Polar Coordinates - Preliminary Questions - Page 617: 3

Circle of radius 2 and centered at the origin. Circle of radius $\sqrt 2$ and centered at the origin. The point $(2,0)$.

(a) $r=2$ is a circle of radius 2 and centered at the origin. (b) $r^2=2$ is a circle of radius $\sqrt 2$ and centered at the origin. (c) $ r\cos \theta =2 \Longrightarrow x=2$; the point $(2,0)$ which is the closest to the origin.