(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Use the functions:

y=x+1, y=0, x=0, x=2

Find the volume when rotated around y=3

Find the volume when rotated around y=-1

2. Relevant equations

PI[tex]\int[/tex] R^{2}dx or perhaps PI[tex]\int[/tex] R^{2}- r^{2}dx

3. The attempt at a solution

i don't think that this is a particularly hard question, but I just can't seem to get the right answer. (perhaps I'm making a silly mistake)

So first I graphed the equations, all in the first quadrant, vertical line at x=2. bounded region looks like a trapezoid.

attempt:

PI[tex]\int[/tex] (from 0-2) of [3-(x+1)]^{2}dx

however the answer is 46pi/3 and I get 8pi/3 <-- very obviously wrong.

is this a washer method problem?

for the next, PI[tex]\int[/tex] (from 0-2) of [1+(x+1)]^{2}dx

i get 32pi/3 and the answer is 50pi/3

thanks :)

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# Homework Help: Volume using the disk method

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