% 练习2第五题
subplot(1,2,1)
t=0:0.1:2*pi;
x=sin(3*t).*cos(t);
y=sin(3*t).*sin(t);
plot(x,y,'-r','Linewidth',5);
subplot(1,2,2)
y1=sin(x);
y2=sin(x).*exp(-0.1*x);
plot(x,y1,'+b',x,y2,'-g')
title('曲线y1 y2')
xlabel('变量x')
ylabel('变量y')
legend('y1','y2');