Interval criteria for oscillation of second-order differential equations with mixed nonlinearities

In this paper, we establish interval criteria for oscillation of the second order forced ordinary differential equations with mixed nonlinearities: (p(t)x')' + q(t)x + Sigma(n)(i=1) q(i)(t)vertical bar x vertical bar(alpha i) sgnx = e(t), where p(t), q(t), q(i)(t), e(t) are continuous functions defined on [ 0, infinity), p(t) is positive and differentiable, alpha(1) > ... > alpha(m) > 1 > alpha(m+1) > ... > alpha(n) > 0 (n > m > 1). No restriction is imposed on the potentials q(t), q(i)(t) and e(t) to be nonnegative. (c) 2007 Elsevier Inc. All rights reserved.