实验4、matlab的计算可视化和GUI设计.doc

p345
subplot(2,2,1)
t1=0:0.1:2;
y1=sin(2*pi*t1);
plot(t1,y1);
title('y=sin(2\pit)')

练习：

subplot(2,2,2)
t2=0:0.1:2;
y2=[exp(-t2);exp(-2*t2);exp(-3*t2)];
plot(t2,y2)
axis([0 2 -0.2 1.2]);
title('y=e-t,y=e-2t,y=e-3t')

练习：

subplot(2,2,3);
t3=[0 1 1 2 2 3 4];
y3=[0 0 2 2 0 0 0];
plot(t3,y3);
axis([0 4 -0.5 3]);
title('脉冲信号')

练习：

subplot(2,2,4);
t4=0:0.1:2*pi;
plot(sin(t4),cos(t4));
axis([-1.2 1.2 -1.2 1.2]);
axis equal;
title('圆')

练习：

P346
x=0:0.1:20;
zeta=0
y1=1-1/sqrt(1-zeta^2)*exp(-zeta*x).*sin(sqrt(1-zeta^2)*x+acos(zeta));
plotx,y1)
zeta=0.3;
y2=1-1/sqrt(1-zeta^2)*exp(-zeta*x).*sin(sqrt(1-zeta^2)*x+acos(zeta));
hold on
plot(x,y2,'r:')
zeta=0.5;
y3=1-1/sqrt(1-zeta^2)*exp(-zeta*x).*sin(sqrt(1-zeta^2)*x+acos(zeta));
plot(x,y3,'g*')
zeta=0.707;
y4=1-1/sqrt(1-zeta^2)*exp(-zeta*x).*sin(sqrt(1-zeta^2)*x+acos(zeta));
plot(x,y4,'m-')
title('二阶系统曲线')
legend('\zeta=0','\zeta=0.3','\zeta=0.5','\zeta=0.707')
grid on
gtext('\zeta=0')
gtext('\zeta=0.3')
gtext('\zeta=0.5')
gtext('\zeta=0.707')
ginput(3)
zeta =
0
ans =
2.6037 0.9035
13.1106 2.0029
4.2166 1.0380

P347
h_fig=gcf
h_axis=gca
h_line1=gco
h_title=get(gca,'title')
h_text2=findobj(h_fig,'string','\zeta=0.3') h_fig =
1
h_axis =
151.0018
h_line1 =
1
h_title =
152.0018
h_text2 =
Empty matrix: 0-by-1

set(h_line1,'linewidth',5)
set(h_axis,'xgrid','off')
set(gca,'ytick',[0 0.25 05 1.0 1.25 1.5 1.75 2.0])
set(h_title,'color','red','fontsize',13)
set(h_text2,'color','red')
??? Undefined function or variable 'h_axis'.

P349
x=0:0.1:20;
y1=1-1/sqrt(1-zeta^2)*exp(-zeta*x).*sin(sqrt(1-zeta^2)*x+acos(zeta));
y2=1-1/sqrt(1-zeta^2)*exp(-zeta*x).*sin(sqrt(1-zeta^2)*x+acos(zeta));
y3=1-1/sqrt(1-zeta^2)*exp(-zeta*x).*sin(sqrt(1-zeta^2)*x+acos(zeta));
y4=1-1/sqrt(1-zeta^2)*exp(-zeta*x).*sin(sqrt(1-zeta^2)*x+acos(zeta));
y=[y1;y2;y3;y4];
z=[ones(size(x))*0;ones(size(x))*0.3;ones(size(x))*0.5;ones(size(x))*0.707];
plot(x,x,x,x)
surf(x,x,x,x)
??? Input argument "n" is undefined.

Error in ==> zeta at 12
Z = double(zeta(sym(n),sym(X)));

P350
x=0:0.3:2*pi;
y=sin(x);
subplot(2,2,1)
bar(x,y,0.5)
axis([0,2*pi,-1.2,1.2])
subplot(2,2,2)
fill(x,y,'r')
subplot(2,2,3)
stairs(x,y)
subplot(2,2,4)
stem(x,y)

P350
guide