第5章例题源程序.docx

1、第5章例题源程序第5章例题源程序.doc例5.1 在0X2区间内，绘制曲线y=2e-0.5xsin(2x)。x=0:pi/100:2*pi;y=2*exp(-0.5*x).*sin(2*pi*x);plot(x,y)例5.2 绘制曲线t=-pi:pi/100:pi;x=t.*cos(3*t);y=t.*sin(t).*sin(t);plot(x,y);例5.3 用不同线型和颜色在同一坐标内绘制曲线y=2e-0.5xsin(2x)及其包络线。x=(0:pi/100:2*pi);y1=2*exp(-0.5*x)*1,-1;y2=2*exp(-0.5*x).*sin(2*pi*x);x1=(0:12

2、)/2;y3=2*exp(-0.5*x1).*sin(2*pi*x1);plot(x,y1,k:,x,y2,b-,x1,y3,rp);例5.4 用不同标度在同一坐标内绘制曲线y1=e-0.5xsin(2x)及曲线y2=1.5e-0.1xsin(x)。x1=0:pi/100:2*pi;x2=0:pi/100:3*pi;y1=exp(-0.5*x1).*sin(2*pi*x1);y2=1.5*exp(-0.1*x2).*sin(x2);plotyy(x1,y1,x2,y2);例5.5 绘制分段函数曲线并添加图形标注。x=linspace(0,10,100);y=;for x0=x if x0=8

3、y=y,1; elseif x0=6 y=y,5-x0/2; elseif x0=4 y=y,2; elseif x0=0 y=y,sqrt(x0); endendplot(x,y)axis(0 10 0 2.5) %设置坐标轴title(分段函数曲线); %加图形标题xlabel(Variable X); %加X轴说明ylabel(Variable Y); %加Y轴说明text(2,1.3,y=x1/2); %在指定位置添加图形说明text(4.5,1.9,y=2);text(7.3,1.5,y=5-x/2);text(8.5,0.9,y=1);例5.6 用图形保持功能在同一坐标内绘制曲线y

4、=2e-0.5xsin(2x)及其包络线。x=(0:pi/100:2*pi);y1=2*exp(-0.5*x)*1,-1;y2=2*exp(-0.5*x).*sin(2*pi*x);plot(x,y1,b:);axis(0,2*pi,-2,2); %设置坐标hold on; %设置图形保持状态plot(x,y2,k);legend(包络线,包络线,曲线y); %加图例hold off; %关闭图形保持grid %网格线控制例5.7 在一个图形窗口中以子图形式同时绘制正弦、余弦、正切、余切曲线。x=linspace(0,2*pi,60);y=sin(x);z=cos(x);t=sin(x)./(

5、cos(x)+eps);ct=cos(x)./(sin(x)+eps);subplot(2,2,1); plot(x,y);title(sin(x);axis(0,2*pi,-1,1);subplot(2,2,2);plot(x,z);title(cos(x);axis(0,2*pi,-1,1);subplot(2,2,3);plot(x,t);title(tangent(x);axis(0,2*pi,-40,40);subplot(2,2,4);plot(x,ct);title(cotangent(x);axis(0,2*pi,-40,40);请看下面的程序。x=linspace(0,2*p

6、i,60);y=sin(x);z=cos(x);t=sin(x)./(cos(x)+eps);ct=cos(x)./(sin(x)+eps);subplot(2,2,1); %选择22个区中的1号区stairs(x,y);title(sin(x)-1);axis (0,2*pi,-1,1);subplot(2,1,2); %选择21个区中的2号区stem(x,y);title(sin(x)-2);axis (0,2*pi,-1,1);subplot(4,4,3); %选择44个区中的3号区plot(x,y);title(sin(x);axis (0,2*pi,-1,1);subplot(4,4

7、,4); %选择44个区中的4号区plot(x,z);title(cos(x);axis (0,2*pi,-1,1);subplot(4,4,7); %选择44个区中的7号区plot(x,t);title(tangent(x);axis (0,2*pi,-40,40);subplot(4,4,8); %选择44个区中的8号区plot(x,ct);title(cotangent(x);axis (0,2*pi,-40,40);例5.8 分别以条形图、填充图、阶梯图和杆图形式绘制曲线y=2e-0.5x。x=0:0.35:7;y=2*exp(-0.5*x);subplot(2,2,1);bar(x,

8、y,g);title(bar(x,y,g);axis(0,7,0,2); subplot(2,2,2);fill(x,y,r);title(fill(x,y,r);axis(0,7,0,2);subplot(2,2,3);stairs(x,y,b);title(stairs(x,y,b);axis(0,7,0,2);subplot(2,2,4);stem(x,y,k);title(stem(x,y,k);axis(0,7,0,2);例5.9 绘制=sin(2)cos(2)的极坐标图。theta=0:0.01:2*pi;rho=sin(2*theta).*cos(2*theta);polar(t

9、heta,rho,k); 例5.10 绘制y=10x2的对数坐标图并与直角线性坐标图进行比较。x=0:0.1:10;y=10*x.*x;subplot(2,2,1);plot(x,y);title(plot(x,y);grid on;subplot(2,2,2);semilogx(x,y);title(semilogx(x,y);grid on;subplot(2,2,3);semilogy(x,y);title(semilogy(x,y);grid on;subplot(2,2,4);loglog(x,y);title(loglog(x,y);grid on;例5.11 用fplot函数绘制

10、f(x)=cos(tan(x)的曲线。先建立函数文件myf.m：function y=myf(x)y=cos(tan(pi*x);再用fplot函数绘制myf.m函数的曲线：fplot(myf,-0.4,1.4,1e-4)得到如图5.12所示曲线。从图5.12中可看出，在x=0.5附近采样点十分密集。也可以直接用fplot函数绘制f(x)=cos(tan(x)的曲线：fplot(cos(tan(pi*x), -0.4,1.4,1e-4)例5.12 绘制图形：(1)某次考试优秀、良好、中等、及格、不及格的人数分别为：7,17,23,19,5，试用饼图作成绩统计分析。(2)绘制复数的相量图：3+2

11、i、5.5-i和-1.5+5i。subplot(1,2,1);pie(7,17,23,19,5);title(饼图);legend(优秀,良好,中等,及格,不及格);subplot(1,2,2);compass(3+2i,5.5-i,-1.5+5i);title(相量图);例5.13 绘制空间曲线：t=0:pi/50:2*pi;x=8*cos(t);y=4*sqrt(2)*sin(t);z=-4*sqrt(2)*sin(t);plot3(x,y,z,p);title(Line in 3-D Space);text(0,0,0,origin);xlabel(X),ylabel(Y),zlabel

12、(Z);grid;例5.14 已知6x30，15y36，求不定方程2x+5y=126的整数解。x=7:29;y=16:35;x,y=meshgrid(x,y); %在7,2916,35区域生成网格坐标z=2*x+5*y;k=find(z=126); %找出解的位置 x(k),y(k) %输出对应位置的x,y即方程的解例5.15 用三维曲面图表现函数z=sin(y)cos(x)。程序1：x=0:0.1:2*pi;x,y=meshgrid(x);z=sin(y).*cos(x);mesh(x,y,z);xlabel(x-axis),ylabel(y-axis),zlabel(z-axis);tit

13、le(mesh);程序2：x=0:0.1:2*pi;x,y=meshgrid(x);z=sin(y).*cos(x);surf(x,y,z);xlabel(x-axis),ylabel(y-axis),zlabel(z-axis);title(surf);程序3：x=0:0.1:2*pi;x,y=meshgrid(x);z=sin(y).*cos(x);plot3(x,y,z);xlabel(x-axis),ylabel(y-axis),zlabel(z-axis);title(plot3-1);grid;例5.16 绘制两个直径相等的圆管的相交图形。%两个等直径圆管的交线m=30;z=1.2

14、*(0:m)/m;r=ones(size(z);theta=(0:m)/m*2*pi;x1=r*cos(theta);y1=r*sin(theta); %生成第一个圆管的坐标矩阵z1=z*ones(1,m+1);x=(-m:2:m)/m;x2=x*ones(1,m+1);y2=r*cos(theta); %生成第二个圆管的坐标矩阵z2=r*sin(theta);surf(x1,y1,z1); %绘制竖立的圆管axis equal,axis offhold onsurf(x2,y2,z2); %绘制平放的圆管axis equal,axis offtitle(两个等直径圆管的交线);hold of

15、f例5.17 分析由函数z=x2-2y2构成的曲面形状及与平面z=a的交线。x,y=meshgrid(-10:0.2:10);z1=(x.2-2*y.2)+eps; %第1个曲面a=input(a=?);z2=a*ones(size(x); %第2个曲面subplot(1,2,1);mesh(x,y,z1);hold on;mesh(x,y,z2); %分别画出两个曲面v=-10,10,-10,10,-100,100;axis(v);grid; %第1子图的坐标设置hold off;r0=abs(z1-z2)=1; %求两曲面z坐标差小于1的点xx=r0.*x; yy=r0.*y; zz=r0

16、.*z2; %求这些点上的x,y,z坐标，即交线坐标subplot(1,2,2);plot3(xx(r0=0),yy(r0=0),zz(r0=0),*); %在第2子图画出交线axis(v);grid; %第2子图的坐标设置例5.18 在xy平面内选择区域-8,8-8,8，绘制函数的4种三维曲面图。 x,y=meshgrid(-8:0.5:8);z=sin(sqrt(x.2+y.2)./sqrt(x.2+y.2+eps);subplot(2,2,1);meshc(x,y,z);title(meshc(x,y,z)subplot(2,2,2);meshz(x,y,z);title(meshz(x

17、,y,z)subplot(2,2,3);surfc(x,y,z)title(surfc(x,y,z)subplot(2,2,4);surfl(x,y,z)title(surfl(x,y,z)例5.19 绘制标准三维曲面图形。t=0:pi/20:2*pi;x,y,z= cylinder(2+sin(t),30);subplot(1,3,1);surf(x,y,z);subplot(1,3,2);x,y,z=sphere;surf(x,y,z);subplot(1,3,3);x,y,z=peaks(30); meshz(x,y,z);例5.20 绘制三维图形：(1)绘制魔方阵的三维条形图。(2)以

18、三维杆图形式绘制曲线y=2sin(x)。(3)已知x=2347,1827,2043,3025，绘制三维饼图。(4)用随机的顶点坐标值画出五个黄色三角形。subplot(2,2,1);bar3(magic(4)subplot(2,2,2);y=2*sin(0:pi/10:2*pi);stem3(y);subplot(2,2,3);pie3(2347,1827,2043,3025);subplot(2,2,4);fill3(rand(3,5),rand(3,5),rand(3,5), y )例5.21 绘制多峰函数的瀑布图和等高线图。subplot(1,2,1);X,Y,Z=peaks(30);w

19、aterfall(X,Y,Z)xlabel(X-axis),ylabel(Y-axis),zlabel(Z-axis);subplot(1,2,2);contour3(X,Y,Z,12,k); %其中12代表高度的等级数xlabel(X-axis),ylabel(Y-axis),zlabel(Z-axis);例5.22 从不同视点绘制多峰函数曲面。subplot(2,2,1);mesh(peaks);view(-37.5,30); %指定子图1的视点title(azimuth=-37.5,elevation=30)subplot(2,2,2);mesh(peaks);view(0,90); %

20、指定子图2的视点title(azimuth=0,elevation=90)subplot(2,2,3);mesh(peaks);view(90,0); %指定子图3的视点title(azimuth=90,elevation=0)subplot(2,2,4);mesh(peaks);view(-7,-10); %指定子图4的视点title(azimuth=-7,elevation=-10)例5.23 3种图形着色方式的效果展示。z=peaks(20);colormap(copper);subplot(1,3,1);surf(z);subplot(1,3,2); surf(z);shading f

21、lat;subplot(1,3,3);surf(z);shading interp;例5.24 绘制两个球面，其中一个球在另一个球里面，将外面的球裁掉一部分，使得能看见里面的球。x,y,z=sphere(20);%生成外面的大球z1=z;z1(:,1:4)=NaN; %将大球裁掉一部分c1=ones(size(z1);surf(3*x,3*y,3*z1,c1);%生成里面的小球hold onz2=z;c2=2*ones(size(z2);c2(:,1:4)=3*ones(size(c2(:,1:4);surf(1.5*x,1.5*y,1.5*z2,c2);colormap(0,1,0;0.5,

22、0,0;1,0,0);grid onhold off例5.25 隐函数绘图应用举例。subplot(2,2,1);ezplot(x2+y2-9);axis equalsubplot(2,2,2);ezplot(x3+y3-5*x*y+1/5)subplot(2,2,3);ezplot(cos(tan(pi*x), 0,1)subplot(2,2,4);ezplot(8*cos(t),4*sqrt(2)*sin(t),0,2*pi)例5.26 在同一坐标下画红、绿两根不同曲线，希望获得绿色曲线的句柄，并对其进行设置。x=0:pi/50:2*pi;y=sin(x);z=cos(x);plot(x,

23、y,r,x,z,g);H=get(gca,Children); %获取两曲线句柄向量Hfor k=1:length(H) if get(H(k),Color)=0 1 0 %0 1 0代表绿色 Hg=H(k); %获取绿色线条句柄 endendpause %便于观察设置效果set(Hg,LineStyle,:,Marker,p); %对绿色曲线进行设置 例5.27 建立一个图形窗口。该图形窗口没有菜单条，标题名称为“图形窗口示例”，起始于屏幕左下角、宽度和高度分别为300像素点和150像素点，背景颜色为绿色，且当用户从键盘按下任意一个键时，将显示“Hello,Keyboard Key Pres

24、sed.”字样。hf=figure(Color,0,1,0,Position,1,1,300,150,. Name,图形窗口示例,NumberTitle,off,MenuBar,none,. KeyPressFcn,disp(Hello,Keyboard Key Pressed.);例5.28 分别在4个不同的图形窗口绘制出正弦、余弦、正切、余切曲线。要求先建立一个图形窗口并绘图，然后每关闭一个再建立下一个，直到建立第4个窗口并绘图。x=linspace(0,2*pi,60);y=sin(x);z=cos(x);t=tan(x);ct=1./(t+eps);%命令组待用C4=figure(Na

25、me,cotangent(x),NumberTitle,. off);plot(x,ct);axis(0,2*pi,-40,40);C3=figure(Name,tangent(x),DeleteFcn,C4,. NumberTitle,off);plot(x,t);axis(0,2*pi,-40,40);C2=figure(Name,cos(x),DeleteFcn,C3,. NumberTitle,off);plot(x,z);axis(0,2*pi,-1,1);%先创建1个图形窗口并绘制曲线figure(Name,sin(x),DeleteFcn,C2,NumberTitle,off);

26、plot(x,y);axis(0,2*pi,-1,1);例5.29 利用坐标轴对象实现图形窗口的任意分割。clf; %清图形窗口x=linspace(0,2*pi,20);y=sin(x);axes(Position,0.2,0.2,0.2,0.7 ,GridLineStyle,-.);plot(y,x);title(sin(x)-1);axes(Position,0.4,0.5,0.2,0.1);stairs(x,y);title(sin(x)-2); axes(Position,0.55,0.6,0.25,0.3);stem(x,y);title(sin(x)-3);axes(Positi

27、on,0.55,0.2,0.25,0.3);x,y=meshgrid(-8:0.5:8);z=sin(sqrt(x.2+y.2)./sqrt(x.2+y.2+eps);mesh(x,y,z); title(mesh(x,y,z);例5.30 利用曲线对象绘制曲线和。t=0:pi/100:pi/2;y1=sin(2*pi*t);y2=sqrt(3)/2*exp(-4*t).*sin(4*sqrt(3)*t+pi/3);figh=figure;axes(GridLineStyle,:,XLim,0,pi/2,YLim,-1,1);line(XData,t,YData,y1,LineWidth,1)

28、;line(t,y2);grid on例5.31 利用曲线对象绘制和并利用文字对象完成标注。theta=-pi:.1:pi;y1=sin(theta);y2=cos(theta);h=line(theta,y1,LineStyle,:,Color,g);line(theta,y2,LineStyle,-,Color,b);xlabel(-pi leq theta leq pi)ylabel(sin(theta)title(Plot of sin(theta)text(-pi/4,sin(-pi/4),leftarrow sin(-pidiv4),FontSize,12)set(h,Color,r,LineWidth,2) %改变曲线1的颜色和线宽例5.32 利用曲面对象绘制三维曲面z=sin(y)cos(x)。x=0:0.1:2*pi;x,y=meshgrid(x);z=sin(y).*cos(x);axes(view,-37.5,30);hs=surface(x,y,z,Fac