Confused on how to do this question

Question

Consider the following.

 x=9√siny,  0≤y≤π,  x=0;    about y=4



(a) Set up an integral for the volume V of the solid obtained by rotating the region bounded by the given curve about the specified axis.

(b) Use your calculator to evaluate the integral correct to four decimal places.

Answer 1

By shell method v = 2π∫₀^π(4 - y)·9√sinydy = 2962.555