具有正负系数中立型微分方程的正解

On the Positive Solutions of a Kind of Neutral Equations with Positive and Negative Coeffcients

本文研究具有正负系数的中立型微分方程[X（t）-R（t）x（t-r）]'+P（t）x（t-r）-Q（t）x（t-δ）=0.在允许R（t）＋Q（s）ds1不成立的条件下，获得方程（*）存在正解的两个充分条件．

Consider the neutral differential equations with positive and negative coefficientsTwo sufficient conditions for the existence of positive solutions of Eq.(*) are obtained when R(t) + Q(s)ds 1 is not satisfied.