Recent content by gassi

In the first can I subtracct df/dx - df/dy and get y - x - 3x^2 - 3y^2 = 0 which gives y(1-3y) = x(1-3x). Therefore x=y and then get that x=z=y?? I also have to tell wether they are maximum, minimum or saddle points.

I have two problems. I posted the first problem before but I still can´t solve it. Homework Statement Find and classify the critical points of f(x,y,z) = xy + xz + yz + x^3 + y^3 + z^3 Homework Equations - The Attempt at a Solution df/dx = y + z +3x^2, df/dy = x + z + 3y^2...

Homework Statement Find and classify the critical points of f(x,y,z) = xy + xz + yz + x^3 + y^3 + z^3 Homework Equations - The Attempt at a Solution df/dx = y + z +3x^2, df/dy = x + z + 3y^2 and df/dz = x + y + 3z^2 a point x is a critacal point if the gradient equals 0...