Using a Surface Integral for Mathematical Analysis of the Area of an Island

daphnelee-mh
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Homework Statement
(Attached below)
Relevant Equations
A=sqrt[1+(dz/dx)^2+(dz/dy)^2]dA
1593786915216.png

I am not clearly understand what the question requests for, is it okay to continue doing like this ? Kindly advise, thanks
 
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The shape of the island is an upside-down paraboloid. The integral looks like everything is OK except the ##r## limits should be reversed. You want to integrate from the smallest to largest values of ##r## to get a positive answer.
 
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LCKurtz said:
The shape of the island is an upside-down paraboloid. The integral looks like everything is OK except the ##r## limits should be reversed. You want to integrate from the smallest to largest values of ##r## to get a positive answer.
I believe you're right. I looked at it wrong.
 
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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