I am learning about finding the area enclosed by polar curves. I don't understand how to find the limits of integration to use. I know the formula is $\frac12\int_a^b f(\theta)^2\operatorname d\theta$, but how do you find the $a$ and $b$?
Find the area enclosed by $r=\cos(3\theta)$
I know this is a rose with three petals, but how do I figure out what to set $a$ and $b$ as?