Tunc, Cemil2025-05-102025-05-1020090126-67052-s2.0-70249143290https://hdl.handle.net/20.500.14720/16541Tunc, Cemil/0000-0003-2909-8753By constructing a Lyapunov function, a new result is given, which guarantees the non-existence of nontrivial periodic solutions to nonlinear vector differential equation of eighth order: X((8)) + AX((7)) + BX((6)) + CX((5)) + DX((4)) + E (X) triple over dot + F((X) over dot)X + G(X)(X) over dot + H(X) = 0. An example is also established for the illustrations of topic. By this way, our findings raise a new result for the nonexistence of nontrivial periodic solutions related to this nonlinear vector differential equation of eighth order.eninfo:eu-repo/semantics/closedAccessNonlinear Differential EquationEighth OrderPeriodic SolutionLyapunov'S Second (Or Direct) MethodArticle