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Finding Volume using integration 
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#1
Jul308, 02:30 PM

P: 6

1. The problem statement, all variables and given/known data
Find the volume of the solid formed by rotating the region enclosed by: (e^(1x)+2)/y=0/x=0/x=.9 about the y axis 2. Relevant equations Probably disk method i would assume: V=pi*int((f(x)^2) dx from bounds a to b 3. The attempt at a solution V= pi*int(e^(1x)+2)^2) a=0 b=.9 v=pi*int(e^(2x)+4) a=0 b=.9 v=pi*(1/2e^(2x)+4x) v=pi*(1/2e^(2(.9))(1/2e^0)+(4(.9) v=pi*(3.025)(1/2)+3.6 v=6.125pi But my answer is not correct. 


#2
Jul308, 02:47 PM

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P: 26,157

Isn't that for rotation about the xaxis? 


#3
Jul308, 02:49 PM

P: 6

Oh yeah. so then would i change my bounds to a=.9 b=.9



#4
Jul308, 03:22 PM

P: 6

Finding Volume using integration
that doesnt seem to work either



#5
Jul308, 03:47 PM

Sci Advisor
HW Helper
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P: 26,157

Your discs should be "horizontal" discs, centred on the yaxis. 


#6
Jul308, 04:08 PM

P: 6

So i should plug in the given x's to get y's for my bounds?



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