I've done this problem, however not in the way suggested (which I assume is much quicker and easier!)

By evaluating an appropriate double integral, ﬁnd the volume of the wedge lying between the planes and ( ) and the cylinder

(where )

I did it by switching to cylindrical polars and then doing the triple integral as I couldnt see a method using a double integral to get the answer

Using the integral

any help with doing this with a better method?