Find the maximal and minimal values of the function f given by: $$f(x,y) = 2x^2+y^2-4y-4x+1$$ on the triangle bounded by the lines $x = 0,y = 2x, y = 2$
Here is my work: $$f_x =4x-4=0 => x=1$$ $$f_y =2x-4=0 => y=2$$
It appears that (1,2) is not inside the triangle. How could I use that information to evaluate f(x,y)? Thanks.