Hello, Apprentice123!

What does stand for in your equation?

I don't see the need for double integrals . . .Calculate in polar coordinates the area of the region

outside of , and inside

. .

The region is symmetric to the -axis.

. . We can determine the area of the upper half and multiply by 2.

From to , the area is between

. .

From to , the area is between

. .

Add the two areas and multiply by 2 . . .