double integrals in polar coordinates
And this is the answer they have given us:
They converted to polar coordinates. I've seen this type of problem being solved without conversion to polar coordinates. I tried to evaluate the integral without converting to polar and I ended up with a different answer:
But my answer does not agree with the model answer! Shouldn't we end up with the same result regardless of whether we use polar or rectangular coordinates? I appreciate any help because I have an exam tomorrow...