Question

The following are about an infinite region in the 1st quadrant between y=e^-x and the x-axis.

B)Find the volume of the solid generated by revolving the region about the y-axis

Part A was solved below. Does anyone know how to do Part B?

Answer 1

using discs, we have

v = ∫[0,∞] πe^(-2x) dx
= π/2