Existence of periodic solutions for second-order neutral differential equations

Abstract

By means of variational structure and critical point theory, we study the existence of periodic solutions for a second-order neutral differential equation (p(t)x'(t - τ))' + ƒ(t, x(t), x(t - τ), x(t - 2τ)) = g(t), x(0) = x(2kτ), x'(0) = x'(2kτ). where k is a given positive integer and τ is a positive number.