Oscillation criteria for certain forced second-order nonlinear differential equations with delayed argument

Some new sufficient conditions for the oscillation criteria are given for the forced second-order nonlinear differential equations with delayed argument in the form, x″(t)+q(t)f(x(τ(t)))=e(t) The results are based on the information only on a sequence of subintervals of [t0, ∞) rather than on the whole half-line. Our methodology is somewhat different from that of previous authors. Our results generalize and extend some earlier results of Sun [1]. Furthermore, we are able to answer the question in recent paper [1] for the oscillation of bounded solutions of the above equation when f(x) = |x|λsgn x, 0 < λ < 1.