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