How to Approach Proving a Partial Derivative Homework Problem?

xortan
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Homework Statement


I have attached a picture of the problem. The question is the first one.


Homework Equations





The Attempt at a Solution


I tried subbing u and v into the right hand side of the equation. I expanded and simplified but I do not think that is the right way to go about it. If somebody can point me in the right direction that would be very helpful. Thank you!
 

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hi xortan! :wink:
xortan said:
I tried subbing u and v into the right hand side of the equation.

my guess is that it's quicker to start from the left hand side

(you could also "factor" it into (∂/∂x + ∂/∂y)(∂/∂x - ∂/∂y)z)

… show us what you get :smile:
 
Well I am really new at partial derivative, we just started this course. Was doing a single variable calc course last semester and only touched on this stuff briefly at the end. I am not understanding where to go when starting from the left hand side. I asked another one of my instructors and he showed me this "brute force" way of doing it. I got it to a point of



(∂2z/∂x2 = (∂/∂x)(∂z/∂u)2x + ∂z/∂u * 2 + (∂/∂x)(∂z/∂v)2y

I got to deal with the first term now but the question seems to be blowing up and I know there has to be an easier way of doing this
 
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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