有偿20元 求助

function ddeex
t0 = 0;
tfinal = 5;
tspan = [t0, tfinal];
sol = ddesd(@ddefun,@delay,@hist,tspan);
plot(sol.x,sol.y,'.-')
xlabel('time')
ylabel('value')
legend('x','y')
function d=delay(t,y)
d=[t-sin(t);t-cos(t);t-2;t-1];
function h=hist(t)
h=[1;-1];
function dydt = ddefun(t,y,Z)
dydt = [1-0.05*Z(1,1)-0.04*Z(2,2); 2-0.02*Z(1,3)-0.7*Z(2,4)];