The behavior of solutions of second order delay differential equations

In this paper, we study the behavior of solutions of second order delay differential equation y (t) = p1y (t) +p2y (t − τ)+q1y(t) +q2y(t − τ), where p1, p2, q1, q2 are real numbers, τ is positive real number. A basic theorem on the behavior of solutions is established. As a consequence of this theorem, a stability criterion is obtained. © 2006 Elsevier Inc. All rights reserved