Use a double integral to find the area of the region.

The region inside the cardioid r = 1 + cos(θ) and outside the circle r = 3cos(θ).

I found the boundaries to be from pi/3 to 5pi/3 and 3costheta to 1+costheta. But I'm not getting the right answer.. after integrating everything, I get the equation- 1/2 (3theta+2sin2theta-2sintheta). Plugging in the boundaries (5pi/3 and pi/3) I get 10pi/6, but that's not correct. Did I integrate wrong?