OSCILLATIONS OF SOLUTIONS OF NEUTRAL DIFFERENTIAL EQUATIONS WITH VARIABLE COEFFICIENTS AND DELAYS

摘要

Consider the neutral differential equations with variable coefficients and delays [x(t) - p(t)x(t - τ(t))]' + ΣQj(t)x(t-σj(t)) = 0. (1) We establish sufficient conditions for the oscillation of equation (1). Our condition is " sharp" in the sense that when all the coefficients and delays of the equation are constants. Our conclusions improve and generalize some known results.