摘要

In this paper, we study the existence of periodic solutions for Rayleigh equation with a singularity of repulsive type x ''(t) + f(x'(t)) + phi(t)x(t) - 1/x(alpha)(t) = p (t), where is a constant, and phi and p are T-periodic functions. The proof of the main result relies on a known continuation theorem of coincidence degree theory. The interesting point is that the sign of the function is allowed to change for .