How to plot this 3d graph?

Hi to all. How can i plot the graph of z=x^3+y^3+3xy with two lines colored: one described by x=0 and the other described by y=0 , both included in the function graph?

Answer 1

[Jonathan Epperl]

Plot the whole graph with mesh or surf, then hold on, then use plot3 to plot the lines you'd like to emphasize:

x = linspace(-3,3);
[X,Y] = meshgrid( x );
mesh(X,Y, X.^3 + Y.^3+ 3*X.*Y);
hold on;
plot3(x*0, x, x.^3,'r','LineWidth',4);
plot3(x, x*0, x.^3,'r','LineWidth',4);
hold off;

[Michele]

many thanks Jonathan.