function dotq = simple_vibration (t, q)
% ”÷•ª•û’öŽ®�i’P�U“®�j
    global angularfrequency;
    
    theta = q(1);
    omega = q(2);
    
    dottheta = omega;
    dotomega = -(angularfrequency)^2 * theta;
    
    dotq = [dottheta; dotomega];
end
