If $\frac{\partial f}{\partial x}= 0$ when $x = 1$, and $\frac{\partial f}{\partial x} = (2y-x)$
Do we have to replace $x$ by 1? to get the critical coordinate $y$?
If $\frac{\partial f}{\partial x}= 0$ when $x = 1$, and $\frac{\partial f}{\partial x} = (2y-x)$
Do we have to replace $x$ by 1? to get the critical coordinate $y$?