function fangcheng
[t,y]=ode45(@weifen,[0:0.002;200],[1 1 1 1 1]);


figure,plot(y(:,1),y(:,4),'k',0.5*y(:,1),0.5*y(:,4),'k-.');xlabel('x1');ylabel('x4');



function dy=weifen(t,y)
dy=zeros(5,1);


a=10; b=8/3; c=28; d=-6;e=-3;
dy(1)=a*(y(2)-y(1))+y(4)+y(5);
dy(2)=c*y(1)-y(2)-y(1)*y(3)+y(5);
dy(3)=y(1)*y(2)-b*y(3)+y(5);
dy(4)=-y(2)*y(3)+d*y(4);
dy(5)=e*y(1);