volume of an exponential (1 Viewer)

MargaretRose · Jun 4, 2012

y = e ^-x + 1 is rotated about x-axis from x=1 to x=2 , calculate correct to decimal place,
I would love it if you could help

Carrotsticks · Jun 4, 2012

MargaretRose said:
y = e ^-x + 1 is rotated about x-axis from x=1 to x=2 , calculate correct to decimal place,
I would love it if you could help

$V = \pi \int_{1}^{2} (e^{-x}+1)^2 dx = \pi \int_{1}^{2} e^{-2x}+2e^{-x}+1 dx = \pi \left [-\frac{1}{2} e^{-2x} -2e^{-x} + x \right ]_1 ^2 =$

Substitute in the limits to acquire the answer.

Do you require an explanation for what I have done so far?

Carrotsticks · Jun 4, 2012

Haha I must ask, why is the giant product symbol there?

thorax94 · Jun 4, 2012

that was meant to be a pi

, correct my if I'm wrong but the volume formula has a pi and I did the calculation wrong anyway.

kaz1 · Jun 4, 2012

Carrotsticks said:
$V = \int_{1}^{2} (e^{-x}+1)^2 dx = \int_{1}^{2} e^{-2x}+2e^{-x}+1 dx = \left [-\frac{1}{2} e^{-2x} -2e^{-x} + x \right ]_1 ^2 = etc$

Substitute in the limits to acquire the answer.

Do you require an explanation for what I have done so far?

where is your pi

Carrotsticks · Jun 4, 2012

Haha I can't believe I forgot to put the pi there!

Thanks for pointing that out.

MargaretRose · Jun 5, 2012

oh cool, haha thankyou I thought so, the answer I was reading was wrong -.-

volume of an exponential (1 Viewer)

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kaz1

et tu

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