Oscillation criteria for first-order impulsive differential equations with positive and negative coefficients

摘要

Some sufficient conditions are obtained for oscillation of all solutions of the first-order impulsive differential equation with positive and negative coefficients [x(t) - R(t)x(t-tau)]' + P(t)x(t-tau) - Q(t)x(t-sigma) = 0, tau >=sigma > 0, t >= t(0), x(tk+) = lk (x(tk)), k = 1, 2, . . . . Our results improve the known results in the literature. (c) 2007 Elsevier B.V. All rights reserved.