- #1
jasonbay74
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Homework Statement
Calculate the volume of the solid of revolution formed by rotating the region around the y-axis. Apply the shell method.
f(x)=e^x, x=0, y=8
Homework Equations
V=∫2∏x((f(x))-g(x))dx
The Attempt at a Solution
This is what I did: (I integrated from 0 to 8)
V=∫ 2∏x(8-e^x)dx
=2∏∫ (8x-xe^x)
I used integration by parts with u=x, du=1dx, v=e^x, and dv e^x(dx)
giving:
2∏[8∫ xdx-(xe^x-∫ e^x(dx)]
my final answer was -129507.1677
When I apply the disk method using x=ln(y) I get 48.13407626.
These two answers should be the same and I think there's an error in my shell method that I can't figure out?