given that f(x,y) = x^4 + y^ 4 -4xy+4

how do you plot contours for this function so as to show how this function looks like?

what i tried was to let x=0, then z = y^ 4 +4 parabola

let y=0 such that z=^4 +4 parabola

and then let z=0...but i do not know how the function will look when z=0.

after doing these 3 parts, how do i find the contours?

or is there another simplier method to do this?

thansk!