Surf command to plot simple surface

Hi

what is happening here:

close all
x = -1 : 0.1 : 5;
y = x;
[X, Y] = meshgrid(x,y);
Z = 2*X - X*Y + 2*Y; 
surf(X, Y, Z)
xlabel('Ox')
ylabel('Oy')
zlabel('Oz')

Answer 1

[Ravi Narasimhan]

Did you intend to do an element-by-element multiply on X and Y?

https://www.mathworks.com/help/matlab/ref/times.html

close all
x = -1 : 0.1 : 5;
y = x;
[X, Y] = meshgrid(x,y);
Z = 2*X - X.*Y + 2*Y; % Note the .*
surf(X, Y, Z)
xlabel('Ox')
ylabel('Oy')
zlabel('Oz')