How do you use the shell method to set up and evaluate the integral that gives the volume of the solid generated by revolving the plane region y=4x2 and y=0 rotated about the y-axis?

1 Answer
Oct 14, 2015

See the explanation, below.

Explanation:

Here is the region with a thin slice taken parallel to the axis of rotation. (To set up for cylindrical shells.)

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The volume of a representative shell is 2πrhthickness

In this case, we have radius r=x, height h=4x2 and thickness=dx. x varies from 0 to 2, so the volume of the solid is:

20πx(4x2)dx=π20(4xx3)dx=4π