On Oscillation of Second Order Neutral Type Delay Differential Equations

Abstract

Oscillation criteria are obtained by using the so called H-method for the second order neutral type delay differential equations of the form (r(t)psi(x(t))z'(t))' + q(t)f(x(sigma(t))) = 0, t greater than or equal to t(0), where z(t) = x(t) +p(t)x(tau(t)), r, p, q, tau, sigma, is an element of C([t(0), infinity), R) and f, psi is an element of C(R, R). The results of the paper contains several results obtained previously as special cases. Furthermore, we are also able to fix an error in a recent paper related to the oscillation of second order nonneutral delay differential equations. (C) 2003 Elsevier Inc. All rights reserved.