figure()

u=-0.1:0.005:0.1;

v=-0.1:0.005:0.1;

[x,y]=meshgrid(u,v);

z=sin(x-y)./abs(x)+abs(y);

surf(x,y,z);

hold on

% contourf(x,y,z)

% ezplot('x+y=3')

% set(gca,'DataAspectRatio',[  ])

%axis equal

clc

clear

u=-:0.1:;

v=-:0.1:;

[x,y]=meshgrid(u,v);

z=.*x.^ +.*y.^;

surf(x,y,z);

hold on

t=:0.1:;

x1=t;y1=t;z1=-*t;

plot3(x1,y1,z1,'r');

plot3(,,,'r*')

quiver3(, , ,/,/,-/,'g') % 后面向量的3个分量除8是为了缩短长度

grid on

set(gca,'DataAspectRatio',[  ])

%axis equal