Oscillation of forced neutral differential equations with positive and negative coefficients

摘要

Some sufficient conditions are obtained for the oscillation of forced neutral differential equations with positive and negative coefficients [x(t) - R(t)x(t - r)]' + P(t)x(t - τ) - Q(t)x(t -σ) = f(t), t ≥ t_0 where R(t), P(t), Q(t) ∈ C ([t_0, ∞), R~+) , r > 0, τ > 0, σ ≥ 0.