你没给初值,我随便射了 clear allclcf=@(t,y)([y(2);(3*y(1)^2+cos(y(1)))/(3*y(2)^2)]);[t,Y]=ode45(f,[0 10],[1 1]);plot(t,Y(:,1),t,Y(:,2)),legend('X','dX/dt')