Rotate a Circle Around the X/Y Axis - Cylindrical Shells

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Homework Statement


Rotate the region bound by the given curve by about the x and y axis. Find the volume through the cylindrical method.
x^2 + (y-1)^2 = 1


Homework Equations


Cylindrical method: ∫2∏xf(x)dx
Slice Method: ∫A(x)dx


The Attempt at a Solution


x^2 + (y-1)^2 = 1
x = √(2y - y^2)

∫2∏x(√(1-x^2)+1)dx from -1 to 1
But this simplifies to 0... What am I doing wrong?
 
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Help, please?
 
What do you mean by rotation "about the x and y axis". I know how to rotate around a single axis but not two.
 
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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