Finding the Mass of a Solid in 3d

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Homework Statement


Find the mass of the solid bounded by the cylinder x^2+y^2=2x and the cone z^2=x^2+y^2 if the density is \delta = \sqrt{x^2+y^2}

[b2. The attempt at a solution[/b]
I had some trouble looking at how to set up the limits on this integral. What I came up with was:
2 \int_0^2 \int_0^{\sqrt{2x^2+2x}} \int_0^{\sqrt{x^2+y^2}} \sqrt{x^2+y^2} dzdydx
= 2 \int_0^2 x^2\sqrt{x^2+y^2} + ((\sqrt{x^2+y^2})^3)/3 dx
And this is just an ugly integral. I tried doing it in cylindrical coordinates but it wasn't working out terribly well that way either. Any hints? Thanks!
 
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Nevermind, I got an answer. Can anyone confirm 6\pi?
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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