(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

w= f(x,y)

x = u + v Verify that Wxx - Wyy = Wuv

y = u - v

2. Relevant equations

3. The attempt at a solution

I know how to find Wu or Wv but I have no idea on how to proceed to find the 2nd order derivative (or 3rd,4rth etc.. obviously). I assume this somehow uses the chain rule but I had no idea on how to apply it in this situation. Thank you!

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# The chain rule for 2nd+ order partial differential equations

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