odefun1

function F=odefun1(t0,x)
global u;
        if t0<0.8
            U=u(1);
        elseif t0<1.6
            U=u(2);
        elseif t0<2.4
            U=u(3);
        elseif t0<3.2
            U=u(4);
        else
            U=u(5);
        end
F = [x(2); -1*x(1)-2*x(2)+1*U;1*x(1)^2+U^2];
end