International Journal of Mathematics and Mathematical Sciences
Volume 21 (1998), Issue 3, Pages 493-497
doi:10.1155/S0161171298000702
Necessary and sufficient conditions for the oscillation of delay differential equation with a piecewise constant argument
Department of Mathematics, Faculty of Education, Ain Shams University, Roxy , Cairo, Egypt
Received 13 August 1996; Revised 18 March 1997
Copyright © 1998 H. A. Agwo. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
The characteristic equation for an equation with continuous and piecewise constant
argument in the form
x˙(t)+px(t−τ)+qx([t−k])=0 where p, q∈ℜ, τ∈ℜ+and k∈ℵ is presented, which when
q=0 reduces to
f(λ)=λ+e−λτ=0
and when p=0 reduces to
λ−1+qλ−k=0.
Also, the necessary and sufficient conditions for oscillation are obtained.