# Selecting the correct bounds for polar integrals

Hi!

Here's a question I am working on:

Double integral of arctan(y/x).

where R: 1≤x2+y2≤4, 0≤y≤x.

I have the bounds for r as 1 to 2, but for θ I don't know if I should use ∏/4 to ∏/2 or 0 to ∏/2. How do I know which one?

The integration is easy, but I need help with the bounds.

Thanks.