Find the critical points when $f(x,y) = x^2 + y^2 + 1$
This is just a simplified version of a much harder question I am doing.
I am hung up on the equation as I do not know to find the critical point since $f'(x,y)$ for $x$ is just $2x$.
In what way am I meant to follow this up to get the critical point. Any advice/help would be much appreciated. Thank you.