Question

How do you graph `r= 5cos 2 theta`?

Answer 1

Draw the graph through `(5, 0), (5sqrt3/2, pi/12), (5/2, pi/6) and (0, pi/4)`. Use symmetry about `theta=0`.

Explanation:

This is a particular case of the rose curve `r = a cos ntheta`, with just one petal. When n is odd, we get n petals.