bilibili地址：
https://www.bilibili.com/video/av9810059?from=search&seid=8719190082089703237
Matlab入门教程07
任务一：画二次曲线，三次曲线
>> x=-3:0.1:3;
>> y1=x.^2;
>> y2=x.^3;
>> axis equal
>> plot(x,y1,'green-o',x,y2,'blue-o')
>> bar(y1)
任务二：三维图像螺旋线上升
>> theta=0:pi/50:6*pi;
>> x=cos(theta);
>> y=sin(theta);
>> plot(x,y)
>> z=0:300;
>> plot3(x,y,z)俯视图
螺旋上升
最终希望达成目标，如下：
x = -5:0.1:5;
y=x.*x;
x2=-5:0.1:5;
y2=x2.^3;
>> plot(x,y)
>> hold on;
>> plot(x2,y2)
>> grid on;
>> title('x^2 vs x^3');
>> xlabel('x-axis');
>> ylabel('y-axis');
Matlab入门教程08
1
subplot(2,3,1)
x=-4:0.1:4;
y1=sin(x);
y2=sin(2.*x);
y3=sin(3.*x);
y4=sin(4.*x);
subplot(2,2,1);
plot(x,y1);
title('y=sin(x)');
subplot(2,2,2);
plot(x,y2);
title('y=sin(2x)');
subplot(2,2,3);
plot(x,y3);
title('y=sin(3x)');
subplot(2,2,4);
plot(x,y4);
title('y=sin(4x)');
x=-4:0.1:4;
y1=sin(x);
y2=sin(2.*x);
y3=sin(3.*x);
y4=sin(4.*x);
subplot(2,2,1);
plot(x,y1);
title('y=sin(x)');
subplot(2,2,2);
plot(x,y2);
title('y=sin(2x)');
subplot(2,2,[3,4]);
plot(x,y4);
title('y=sin(4x)');1
曲线和曲面是不同的：
surf()函数
画抛物面
>> x=-3:1:3;
y=-3:1:3;
[X,Y] = meshgrid(x,y);
Z=X.^2 + Y.^2;
>> X
X =
-3 -2 -1 0 1 2 3
-3 -2 -1 0 1 2 3
-3 -2 -1 0 1 2 3
-3 -2 -1 0 1 2 3
-3 -2 -1 0 1 2 3
-3 -2 -1 0 1 2 3
-3 -2 -1 0 1 2 3
>> Y
Y =
-3 -3 -3 -3 -3 -3 -3
-2 -2 -2 -2 -2 -2 -2
-1 -1 -1 -1 -1 -1 -1
0 0 0 0 0 0 0
1 1 1 1 1 1 1
2 2 2 2 2 2 2
3 3 3 3 3 3 3
>> Z
Z =
18 13 10 9 10 13 18
13 8 5 4 5 8 13
10 5 2 1 2 5 10
9 4 1 0 1 4 9
10 5 2 1 2 5 10
13 8 5 4 5 8 13
18 13 10 9 10 13 18
>> surf(X,Y,Z)