How do you graph r = 3 + 3 cos thetar=3+3cosθ?

1 Answer
Feb 18, 2016

Tabulation shows the curve passes successively through the polar (6, 0), (3, pi/2π2), (0, piπ), (3, 3piπ/2) and (6, 2piπ). A smooth curved join gives the cardioid (heart-like) closed curve

Explanation:

r is periodic with period 2piπ. cos thetaθ = cos (-thetaθ). So, the curve is symmetrical about the initial line thetaθ = 0. The curve has a cusp at the pole (0, 0). A major portion lie in the first and fourth quadrants..