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On the existence of the periodic solutions of Rayleigh equation. (Chinese. English summary) Zbl 0812.34037
Summary: We study the existence of periodic solutions of an $$n$$-dimensional Rayleigh equation. Using coincidence degree theory developed by Mawhin, we find two sufficient conditions for the existence of periodic solutions of the Rayleigh equation. Particularly, the uniqueness of periodic solutions of the Duffing equation is considered.

##### MSC:
 34C25 Periodic solutions to ordinary differential equations