Change to polars double integral

Kuma
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Homework Statement



Here is the question

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Homework Equations


The Attempt at a Solution



So converting to polars by x = r cos θ, y = r sin θ gives me r^5 in the inner integral

but how do you convert the ranges?

y goes from 0 to sqrt 1 - x^2, so that is just r, I could tell just by looking at it, but in a harder question how do you derive the range in terms of r? x goes from 0 to 1, but how do you convert that in terms of θ (an angle)?
 
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Have you sketched the region of integration?
 
Draw the domain of integration in the x,y plane (like in the figure) and find the ranges of θ and r from there.

ehild
 

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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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