[新版]用matlab画分段函数y

用matlab画分段函数y=sin(x), 当y<0时 y=0 ； 当y>0.8时 y=0.8

00000000000000000000x=-2:0.1:2; y=0.*(x<0)+sin(x).*(x<=0.8&x>=0)+0.8*(x>0.8);

plot(x,y,'r')

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例2 高数中的的取整函数y=[x] Ex-1: >> x=0:0.001:4;

>> y=0*(x<1&x>=0)+(x<2&x>=1)+2*(x<3&x>=2)+3*(x<4&x>=3);>> plot(x,y,'-r')

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Ex-2: x=0:0.001:4;

y=0*(x<1&x>=0)+(x<2&x>=1)+2*(x<3&x>=2)+3*(x<4&x>=3);k1= find(x==1); k2= find(x==2); k3= find(x==3); k4= find(x==4);plot(x(1:k1-1),y(1:k1-1),'b', x(k1+1:k2-1),y(k1+1:k2-1),'r')hold on

plot(x(k2+1:k3-1),y(k2+1:k3-1),'c',x(k3+1:k4-1),y(k3+1:k4-1),'m')hold off

00000000000000000000000000000000000000000000000000000000000000000000000000000

0000000000000000

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例3 matlab 绘制分段函数 x>=1,y=exp(-(x-1)^2); x<1,y=x^2.其中曲线为绿虚线，并进行标注 x=-4:0.01:4;

y=(x<1).*(x.^2)+(x>=1).*(exp(-(x-1).^2)); plot(x,y,'b')

text(-2,5,'\\leftarrow y=x^2','FontSize',9) text(2,0.7,'\\leftarrow y=exp(-(x-1)^2)','FontSize',9)

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