Abdi, Tadesse (PhD)Tunshura, Aman2020-12-152023-11-042020-12-152023-11-042014-03-03http://etd.aau.edu.et/handle/123456789/24066We use a direct variational method in order to investigate the dependence on parameter for the solution of the following Du ng type equation with Dirichlet boundary conditions x (t) + r(t)x_ (t) 􀀀 Fx(t; x(t)) 􀀀 f(t) = 0 x(0) = x(1) = 0 and we observe that some outline of variational approach, in order to use this method.enDirichlet Boundary ProblemDuffing Equation and Lower SemicontinuityThesis