Ademola, T. A.Arawomo, P. O.Idowu, A. S.2023-03-212023-03-212017-060717-6279ui_art_ademola_stability_2017Proyecciones Journal of Mathematics 36(2), pp. 257-282http://ir.library.ui.edu.ng/handle/123456789/8103Stability, boundedness and existence of a unique periodic solution to certain second order nonlinear delay differential equations is discussed. By employing Lyapunov’s direct (or second) method, a complete Lyapunov functional is constructed and used to establish sufficient conditions, on the nonlinear terms, that guarantee uniform asymptotic stability, uniform ultimate boundedness and existence of a unique periodic solution. Obtained results complement many outstanding recent results in the literature. Finally, examples are given to show the effectiveness of our method and correctness of our results.enSecond orderNonlinear differential equationUniform stabilityUniform ultimate boundednessExistence of a unique periodic solutionsArticle