we detect six solutions,
two of them are quasiperiodic bifurcated from symmetric pair of 1 : 1 PR, pair of 1 : 3 PR, steady state of pendulum and
1L1R PR. For larger values of excitation we also find chaotic attractor, e.g., for m ¼ 1:6, f¼1.95 (see Fig. 6(e)). Usually the
chaotic solution dominates the whole phase space and the coexisting attractors have small basins of attraction, and such a
situation is also observed in the investigated system (7). I