% funktionextrem

c=0.5;
[x,y]=meshgrid(-2:0.1:2);
z=x.^4+y.^4-4*c^2*x.*y;
figure;
mesh(x,y,z);
title('f2(x,y) mesh');
xlabel('x');
ylabel('y');

figure;
contour(x,y,z);
title('f2(x,y) contour');
xlabel('x');
ylabel('y');