On oscillatory and asymptotic behavior of fourth order nonlinear neutral delay dynamic equations with positive and negative coefficients

In this paper, oscillatory and asymptotic properties of solutions of nonlinear fourth order neutral dynamic equations of the form (r(t)(y(t) + p(t) y(alpha(1)(t)))(Delta 2))(Delta 2) + q(t)G(y(alpha(2)(t)) - h(t) H (y(alpha(3)(t))) = 0 (H) and (r(t)(y(t) + p(t) y(alpha(1)(t)))(Delta 2))(Delta 2) + q(t)G(y(alpha(2)(t))) - h(t)H(y(alpha(3)(t))) = f(t), (NH) are studied on a time scale under the assumption that and for various ranges of p(t). In addition, sufficient conditions are obtained for the existence of bounded positive solutions of the equation (NH) by using Krasnosel'skii's fixed point theorem.