摘要
By using the theory of coincidence degree, we study a kind of periodic solutions to second order differential equation with a deviating argument such as x″(t) + f(x′(t)) + h(x(t))x′(t) + g(x(t - τ(t))) ≈ p(t), some sufficient conditions on the existence of periodic solutions are obtained.
基金
the Natural Science Foundation of Anhui Province(050460103)
the Natural Science Foundation by the Bureau of Education of Anhui Province(2005kj031ZD)