On the Existencc of Asymptotically Decaying Positive Solutions of Second Order Neutral Differential Equations

摘要

正The existence of postive solutions of second order neutral differential equation.(x（t）-cx（t-r）〃+P（t）x(g（t）=0,t≥t₀ （*）is investigated some sufficient conditions are given for the existence of positivesolutions with asymptotic clecay of（*）for the cases of constant sign and noncon-stant sing of coefficients.It also is shown that one of these sufficient conditionsis necessasy.