Abstract
The purpose of this paper is to study the distribution of zeros of solutions to a first-order neutral differential equation of the form
[x(t) + p(t)x(t - tau)]' + q(t)x(t - sigma) = 0, t >= t(0),
where p is an element of C([t(0), infinity), [0, infinity)), q is an element of C([t(0), infinity), (0, infinity)), tau, sigma > 0, and sigma > tau. We obtain new upper bound estimates for the distance between consecutive zeros of solutions, which improve upon many of the previously known ones. The results are formulated so that they can be generalized without much effort to equations for which the distribution of zeros problem is related to the study of this property for a first-order delay differential inequality. The strength of our results is demonstrated via two illustrative examples.