Oscillation criteria of a certain class of third order nonlinear delay differential equations with damping

In this paper, we are concerned with the oscillation of third order nonlinear delay differential equations of the form r2(t) r1(t)y + p(t)y + q(t)f y g(t) = 0. By using a generalized Riccati transformation and integral averaging technique, we establish some new sufficient conditions which insure that any solution of this equation oscillates or converges to zero. In particular, several examples are given to illustrate the importance of our results. © 2006 Elsevier Inc. All rights reserved.