# Chain Rule

Calculus Level 4

Functions $$f$$ and $$g$$ are such that: $\large f(x,y)=g(u,v)$ where $$u=\dfrac{x+y}{xy}$$ and $$v=\dfrac{x-y}{xy}$$. Find the value of: $\large x^2\frac{\partial f}{\partial x}+y^2\frac{\partial f}{\partial y}+2\frac{\partial g}{\partial u}$

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