AbdGafar Tunde TiamiyuAbosede Temilade ColeKhadeejah James Audu2025-04-242021-09-19Abdgafar Tunde Tiamiyu, Abosede Temilade Cole and Khadeejah James Audu (2021). A Backward Differentiation Formula for Third-Order Initial or Boundary Values Problems Using Collocation Method. Iranian Journal of Optimization, 13(2), 81-92.ISSN: 2588-5723E-ISSN:2008-5427http://repository.futminna.edu.ng:4000/handle/123456789/926A journal publicationWe propose a new self-starting sixth-order hybrid block linear multistep method using backward differentiation formula for direct solution of third-order differential equations with either initial conditions or boundary conditions. The method used collocation and interpolation techniques with three off-step points and five-step points, choosing power series as the basis function. The convergence of the method is established, and three numerical experiments of initial and boundary value problems are used to demonstrate the efficiency of the proposed method. The numerical results in Tables and Figures show the efficiency of the method. Furthermore, the numerical method outperformed the results from existing literature in terms of accuracy as evident in the results of absolute errors producedInitial Value problemsBoundary Value ProblemsThird Order ODEBackward Differentiation FormulaHybrid Linear MultistepArticle