x1=linspace(0,15,100)
y1=sin(x1)
plot(x1,y1)
hold on
plot(x1(34:100),y1(34:100),'color',[0.52941 0.80784 0.98039])
axis([0 15 -2 2])
hold on
theta=pi/50
xx=x1(34:100)*cos(theta)-y1(34:100)*sin(theta)-0.02;
yy=x1(34:100)*sin(theta)+y1(34:100)*cos(theta)-0.31;
plot(xx,yy,'r')
xlabel('时间/s');ylabel('信号值')
