Abstract
This paper contains new estimates for the distance between adjacent zeros of solutions of the first order delay differential equation
x
′
(
t
)
+
p
(
t
)
x
(
t
−
τ
)
=
0
where
p
is a nonnegative continuous function. Our results are new and improve some known criteria. Illustrative examples are given to show the strength of some obtained results over the known ones.