function xp = kolokzad1(t,x )
n = rem(t,3);
u = ((-3/9)*t+3).*(n>1);
e = u-0.5*x(1)^2;
q = x(1)^2;
t = 0:0.01:10-0.01;

xp = [  x(2)
        4*e-x(1)-x(2)
        x(4)
        q-x(3) ];

end


% [t,x] = ode23(@kolokzad1, [0 9], [-1; 2; 0; 1]);
% y=x(:,3);
% plot(t,y)