00:01
We would like to find the volume that is generated by the area that is bounded by these three curves, so this area right here, when that is rotated around the y -axis.
00:12
So in order to do this, we're going to use the method of cylindrical shells, which simply states that the volume is the integral from a to b times of 2 pi times the radius, times the height, times the thickness.
00:28
So for us, in that case, we see that our height would be 4 minus x squared.
00:37
And then our radius, because we're just rotating around the x -axis, oh, excuse me, the y -axis, it would just be equal to x.
00:47
And then our thickness would just be equal to dx.
00:51
So let's go ahead and write that out, a to b, 2 pi, radius of x...