Let us consider the functions for [math]u[/math] and [math]v[/math] such that:[br][br][center][math]u\left(x,y\right)=2x-y[/math][br][math]v\left(x,y\right)=x+y^2[/math][br][/center]When we talk about how [math]f[/math] changes, it would be best to break things down into partial derivatives. [br][br]Then how do we define [math]f'[/math]?