Asymptotic behavior of solutions of neutral nonlinear differential equations

Jozef  Dzurina

Address. Department of Mathematical Analysis,  Faculty of Sciences,  Safarik University,  Jesenna 5,
                04154  Kosice, Slovakia

E-mail: dzurina@kosice.upjs.sk

Abstract.  In this paper we study asymptotic behavior of solutions of second
order neutral functional differential equation of the form
$$
\Big(x(t)+px(t-\tau)\Big)''+f(t,x(t))=0\,.
$$
We present conditions under which all nonoscillatory solutions
are asymptotic to $at+b$ as $t\to\infty$, with $a,b\in R$. The obtained results extend those that are known for equation
$$
u''+f(t,u)=0\,.
$$

AMSclassification. 34K10, 34K25.

Keywords.  Neutral equation, asymptotic behavior.