Find the area of the region that lies inside the curve r=1 + cosΘ and outside of the curve r= 3cosΘ

I set them equal to eachother and solved for Θ = pi/3, 5pi/3

I then set up the integral from pi/3 to pi of (0.5)(1+cosΘ)^2 and got

pi - [8+rad(3)]/8

can anyone help me solve this problem

thanks