Oscillation of a higher order neutral differential equation with a sub-linear delay term and positive and negative coefficients
We obtain sufficient conditions for every solution of the differential equation to oscillate or to tend to zero as approaches infinity. In particular, we extend the results of Karpuz, Rath and Padhy (2008) to the case when has sub-linear growth at infinity. Our results also apply to the neutral equation when has sign changes. Both bounded and unbounded solutions are consideted here; thus some known results are expanded.