The behavior of solutions of second order delay differential equations

In this paper, we study the behavior of solutions of second order delay differential equationy″(t)=p1y′(t)+p2y′(t−τ)+q1y(t)+q2y(t−τ),y″(t)=p1y′(t)+p2y′(t−τ)+q1y(t)+q2y(t−τ), where p1p1, p2p2, q1q1, q2q2 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.