clear

x=linspace(-3,3,15);
y=linspace(-3,3,10);
[X,Y]=meshgrid(x,y); %x varia por columnas, y varia por filas 
Z=X.^2+Y.^2;
figure(1)
surf(X,Y,Z,gradient(Z))
view(70,15)

figure(2)
subplot(2,2,1)
surf(X,Y,Z,gradient(Z))
subplot(2,2,2)
surf(X,Y,Z,gradient(Z))
shading flat
subplot(2,2,3)
surf(X,Y,Z,gradient(Z))
shading interp
subplot(2,2,4)
surf(X,Y,Z,gradient(Z))
shading faceted %(por defecto) 
%title(num2str(Z(1,1)))

figure(3)
mesh(X,Y,Z);
xlabel('x'),ylabel('y'),zlabel('z')

figure(4)
pcolor(Z)
xlabel('x'),ylabel('y'),zlabel('z')

figure(5)
v=[1,2.5,4,8,9]
cs=contour(X,Y,Z,v)
clabel(cs)