Positive solutions of second-order delay differential equations with a damping term

In the paper, the existence of positive solutions is studied for the second-order delay differential equation with a damping term ẍ(t)+a(t)ẋ(t)+b(t)x(h(t))=0 using a comparison with the integro-differential equation ẏ(t)+∫t0te−∫sta(ξ)dξb(s)y(h(s))ds=0. Explicit non-oscillation criteria and comparison type results are derived.