Describe the Poincar section corresponding to a periodic function when the sampling interval is one-third of the

Describe the Poincaré section corresponding to a periodic function when the sampling interval is one-third of the period.

A DOF system with a cubic nonlinearity has a linear natural frequency of \(120 \mathrm{rad} / \mathrm{s}\). The system is forced by harmonic excitations at different frequencies \(\omega_{1}\) and \(\omega_{2}\). What resonances does the system have under the given circumstances.