MATLAB图形绘制练习（二）

比眉伴天荒 2022-05-20 06:26 336阅读 0赞

**多图形显示**

**1.图形分割**

**subplot(m,n,p)将当前窗口分割成m\*n个视图区域，并指定第p个视图为当前视图。**

**subplot('position',\[left right width height\])：产生的新子区域的位置由用户指定，后面的四元组为区域的具体参数控制，宽高的取值范围都是\[0,1\]。**

>> subplot(2,1,1)
    >> subplot(2,1,2)

![70][]

**显示4\*4图形分割。**

>> t1=(0:11)/11*pi;
    >> t2=(0:400)/400*pi;
    >> t3=(0:50)/50*pi;
    >> y1=sin(t1).*sin(9*t1);
    >> y2=sin(t2).*sin(9*t2);
    >> y3=sin(t3).*sin(9*t3);
    >> subplot(2,2,1),plot(t1,y1,'r.')
    >> axis([0,pi,-1,1]),title('(1)点过少的离散图形')
    >> subplot(2,2,2),plot(t1,y1,t1,y1,'r.')
    >> axis([0,pi,-1,1]),title('(2)点过少的连续图形')
    >> subplot(2,2,3),plot(t2,y2,'r.')
    >> axis([0,pi,-1,1]),title('(3)点密集的离散图形')
    >> subplot(2,2,4),plot(t3,y3)
    >> axis([0,pi,-1,1]),title('(4)点足够的连续图形')

![70 1][]

**2.图形叠加**

**图形保持命令hold on/off控制原有图形的保持与不保持**

>> N=9;
    >> t=0:2*pi/N:2*pi;
    >> x=sin(t);y=cos(t);
    >> tt=reshape(t,2,(N+1)/2);
    >> tt=flipud(tt);
    >> tt=tt(:);
    >> xx=sin(tt);yy=cot(tt);
    >> plot(x,y)
    >> hold on
    >> plot(xx,y)
    >> hold off
    >> plot(xx,y)

**![70 2][]**

**![70 3][]**

**fplot命令是专门用于画图像的命令。用其所做出来的图像要比用plot命令做出的图像光滑准确。**

**做出函数y=sinx、y=(sinx)^3，x∈\[1,4\]的图像。**

>> subplot(2,1,1),fplot(@(x)sin(x),[1,4]);
    >> subplot(2,1,2),fplot(@(x)sin(x).^3,[1,4]);

![70 4][]

**做出函数y=sin(1/x),x∈\[0.01,0.02\]的图像。**

>> x=linspace(0.01,0.02,50);
    >> y=sin(1./x);
    >> subplot(2,1,1),plot(x,y)
    >> subplot(2,1,2),fplot(@(x)sin(1./x),[0.01,0.02])

![70 5][]

**ezplot命令用于将一个符号函数图形化。**

**绘制隐函数f1(x)=e^(2x)sin(2x),x∈(-π,π)的图像。**

>> syms x
    >> f1 = exp(2*x)*sin(2*x);
    >> subplot(2,2,1),ezplot(exp(2*x),[-pi,pi])
    >> subplot(2,2,2),ezplot(sin(2*x))
    >> subplot(2,2,3),ezplot(exp(2*x)+sin(2*x),[-pi,pi,0,2*pi])
    >> subplot(2,2,4),ezplot(f1,[-4*pi,4*pi])

![70 6][]

参考：MATLAB2016高级应用与仿真，李津、刘涛等编著，机械工业出版社

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