回复 2楼 azzbcc
clc;clear;
t0=0;tf=5;
[t,y]=ode45('f1',[t0,tf],[0,0,0,0]);
figure;
plot(t,y(1),'r',t,y(3),'b');
hold on
%%%%%%%%
function dy=f1(t,y)
dy=zeros(4,1);
dy(1)=y(2);
dy(3)=y(4);
dy(2)=-y(2)-10*y(1)-0.25*y(4)-2.5*y(3)
dy(4)=-554/256*y(4)-5540/256*y(3)-100/256*y(2)-1000/256*y(1)
求指导