I have seen examples where the thetas are preset, but I have trouble with the ones where I have to find them.

Find the area of the regions.

1. Inside the oval limacon r = 4 + 2 cos(theta)

I found the value for theta... -4 = 2cos(theta)

-2 = cos(theta) -> arccos(-2) = theta... but the calc says this is undefined.

Need help