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## Homework Statement

Rotate around the y-axis the region above the graph of y=x

^{3}that is bounded by the lines x=1 and y=8

## Homework Equations

dV= (2pix)(y)(dx)

## The Attempt at a Solution

dV = (2pix)(y)dx

dV = (2pix)(x^3) dx

= 2pix^4

I integrated from y = 1 to y=8 and I get the wrong answer.

V = 2∏

_{x=1}∫

^{x=2}x^4 dx

V = 2∏[1/5x^5]

^{2}

_{1}

Can someone please explain to me, how I would set up this equation? Something to do with the first function subtracting the second function which I think is x=1

Here is a graph: http://www3.wolframalpha.com/Calculate/MSP/MSP15491a07c8557bi4590b00001ibd52eb6gcc3177?MSPStoreType=image/gif&s=21&w=366&h=298&cdf=RangeControl [Broken]

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