Hello, I find it hard to understand the regions of integral when solving multivariable integrations, such as in double integration.

I would like to discuss and learn about strategies and methods on how to go through the process of facilitating knowledge about the region/interval of the integration. Would you like to share your thought process when you solving a double integral in polar coordinates? for example:

Regards

/Anhard

I understand the conversion from cartesian to polar coordinates and also the resoluton of the integral itself. But can you explain how you set the limits of integration. This is the tricky point for me.