画出<衡痕贤伎strong>衰减振荡曲线![MATLAB操作教程：[4]计算结果的图形表示1](https://exp-picture.cdn.bcebos.com/f0848bee41c1b72755dd053d1a2ca5cadde89827.jpg)
及其它的包络线![MATLAB操作教程：[4]计算结果的图形表示1](https://exp-picture.cdn.bcebos.com/ccc83ec5260f8835d6055a6bce07880139708627.jpg)
。的取值范围是![MATLAB操作教程：[4]计算结果的图形表示1](https://exp-picture.cdn.bcebos.com/890dfb4a2f27e7ef368968b419dd3340b7f3f527.jpg)
t=0:pi/50:4*pi;
y0=exp(-t/3);
y=exp(-t/3).*sin(3*t);
plot(t,y,'-r',t,y0,':b',t,-y0,':b')
grid
![MATLAB操作教程：[4]计算结果的图形表示1](https://exp-picture.cdn.bcebos.com/4b626771fe1d96d82a9662952ccd0c6efaf2e127.jpg)
画出<衡痕贤伎strong>衰减振荡曲线及其它的包络线。的取值范围是
t=0:pi/50:4*pi;
y0=exp(-t/3);
y=exp(-t/3).*sin(3*t);
plot(t,y,'-r',t,y0,':b',t,-y0,':b')
grid