>> x = -pi:pi/10:pi;                          % 从-pi到pi等间距(步长 pi/10)取点
>> y = tan(sin(x)) - sin(tan(x));             % 计算函数值
>> plot(x,y,'-rs','LineWidth',2,...
                  'MarkerEdgeColor','k',...
                  'MarkerFaceColor','b',...
                  'MarkerSize',6)
subplot(2, 2, 3);
R =sqrt(X.^2 + Y.^2) + eps;
[X,Y]=meshgrid(-8:0.5:8);
Z = sin(R)./R;
surf(X, Y, Z);
title("surf()");
  
示例: 同一函数在不同画法下的外观
  
R =sqrt(X.^2 + Y.^2) + eps;
[X,Y] = meshgrid(-8:0.5:8);
Z = sin(R)./R;
subplot(2, 2, 1);
mesh(X, Y, Z);
title("mesh( )");
subplot(2, 2, 2);
meshz(X, Y, Z);
title("meshz( )");
subplot(2, 2, 3);
meshc(X, Y, Z);
title("meshc( )");
subplot(2, 2, 4);
surfc(X, Y, Z);
title("surfc( )");
[x,y]=meshgrid(-2:0.01:2);
z1 = x.^2 - 2*y.^2;
z2 = 2*x - 3*y;
mesh(x,y,z1);
mesh(x,y,z2);
cr  = abs(z1 - z2) < 0.01;
avg = (z1+z2)./2;
plot3(x(cr), y(cr), avg(cr),'*k');
subplot(2,2,4);
[c,h] = contourf(peaks); % 填色等值线 
clabel(c,h);             % 标记等值线 
colorbar;
      
例: contourslice绘制flow场剖面等值线
      
[X,Y,Z,V] = flow;          % 提取数据
Sx=1:9; Sy=[]; Sz=0;       % 选取剖面位置
cvals = linspace(-8,2,10); % 取10条等值线
contourslice(X,Y,Z,V,Sx,Sy,Sz,cvals);
axis([0,10,-3,3,-3,3]);
daspect([1,1,1]);  % 坐标轴的纵横比
campos([0,-20,7]); % 设置相机的位置
box on             % 显示坐标盒子
      
例: contourslice绘制flow场剖面等值线
      
[x,y,z] = meshgrid(-2:.2:2);
v=x.*exp(-x.^2-y.^2-z.^2); % 生成三维标量场
slice(v,[5 15],15,10);     % 绘制剖面颜色图
axis([0 21 0 21 0 21]);
hold on
colorbar('horiz');
colorbar('vert');
view([-25 65]);
  
例: 使用 streamline 和 quiver 共同表现二维矢量场
  
hold on
[x,y] = meshgrid(0:0.1:1,0:0.1:1);
u=x; v=-y;          % 生成矢量场
startx = 0.1:0.1:1; % 设定流线起点阵列
starty = ones(size(startx));
streamline(x,y,u,v,startx,starty);
                    % 绘制流线图
quiver(x,y,u,v);    % 绘制箭头图
在 Matlab 命令界面中输入 help 即可获得对某个函数的描述, 包含所有可能的引用方法, 甚至可以提供联想建议.
实际上, Matlab help 命令足以解决绝大多数问题, 熟练使用 help 命令可以大大减少上网搜索浪费的时间.
>> help linspace
 linspace Linearly spaced vector.
    linspace(X1, X2) generates a row vector of 100 linearly
    equally spaced points between X1 and X2.
    linspace(X1, X2, N) generates N points between X1 and X2.
    For N = 1, linspace returns X2.
    Class support for inputs X1,X2:
       float: double, single
    See also logspace, colon.
    Reference page for linspace
    Other functions named linspace
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