Shell Method Question - Where am I wrong?

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Homework Statement



Find the volume of the solid created when the area between the function y=xe0.5x and the x-axis (for 0≤x≤2) is rotated about the line x=-2

Homework Equations



Shell Method: Vs = ∫ 2∏r * f(x)

The Attempt at a Solution



r = x + 2

r * f(x) = x2e0.5x + 2xe0.5x

Thus, 2∏∫ (x2e0.5x + 2xe0.5x)dx {from 0 to 2}

My final answer is 16∏(e1 - 1) ≈ 86.3703

Did I make a mistake somewhere?
 
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It looks correct.
 
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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