hey, i need help in solving the equation of a mathieu oscillator (ignoring damping) and showing how the condition for max parametric resonance is doubling of the natural frequency . ( got viva 2morro. im so going to suck) D^2x + K(t)x =0 (Ko is the constant natural frequency when no perturbation present. D^2 is the second order time derivative of displacement x) . and, um, i kno precious little maths. for differential equations with variable coeffs, jst Frobenius method to seek series solns.