matlab ode·½³ÌµÄÇó½â

function dx=sim001(t,x)
k=10;
dx=zeros(2,1);
dx(1)=x(2);
dx(2)=-x(1)+k*x(2)-k*x(1)^2*x(2)+10*sin(2*t);
end

clc;clear all;
t0=0;tf=40;
x0=[-2,2];
[t,x]=ode45(@sim001,[t0,tf],x0);
plot(t,x(:,1))
plot(t,x(:,2))