The transfer function is in the form: \[ \frac{10}{s^2 + 2\zeta \omega_n s + \omega_n^2} \] Comparing coefficients, $\omega_n^2 = 10$ and $2\zeta \omega_n = 3$.
Thus, $\omega_n = \sqrt{10}$ and $\zeta = \frac{3}{2\sqrt{10}} \approx 0.5$.
For an input voltage \( v = 10 \sin 1000t \), the Thevenin's impedance at the terminals X and Y for the following circuit is