Hello all.

My problem is this:

Rotate the region bounded by the given curves about the line indicated. Obtain the volume of the solid by the method of shells. (give your answer in terms of http://www.ilrn.com/ilrn/formulaImage?f=%5Cpi&ns=0.)

$\displaystyle x=sqrt(4-y^2)$ y-axis, x-axis. About the y-axis

I've been working on this for hours and cannot get it. Help would be appreciated.