function dx=dym(t,x,flag,para)
global A B C D
u=para;
dx=zeros(4,1); 

%State equation for one link inverted pendulum
%dx=A*x+B*u;
dx=[x(2);
    (x(4)^2*sin(x(3))-3.67875*sin(2*x(3))-50.9784*x(2)+1)/(11-0.75*cos(x(3))^2)+para/(1+0.1*(1-0.75*cos(x(3))^2));
    x(4);
    (7.3575*sin(x(3))-0.75*cos(x(3))*(x(4)^2*sin(x(3))-3.67875*sin(2*x(3))-50.9784*x(2)+1)/(11-0.75*cos(x(3))^2))-0.75*cos(x(3))*para/(1+0.1*(1-0.75*cos(x(3))^2))];