Abstract
This article deals with the asymptotic behavior of nonoscillatory solutions of fourth order linear differential equation where the coefficients are perturbations of con- stants. We define a change of variable and deduce that the new variable satisfies a third order nonlinear differential equation. We assume three hypotheses. The first hypoth- esis is related to the constant coefficients and set up that the characteristic polynomial associated with the fourth order linear equation has simple and real roots. The other two hypotheses are related to the behavior of the perturbation functions and establish asymptotic integral smallness conditions of the perturbations. Under these general hy- potheses, we obtain four main results. The first two results are related to the application of a fixed point argument to prove that the nonlinear third order equation has a unique solution. The next result concerns with the asymptotic behavior of the solutions of the nonlinear third order equation. The fourth main theorem is introduced to establish the existence of a fundamental system of solutions and to precise the formulas for the asymptotic behavior of the linear fourth order differential equation. In addition, we present an example to show that the results introduced in this paper can be applied in situations where the assumptions of some classical theorems are not satisfied.
Highlights
Linear fourth-order differential equations appear as the most basic mathematical models in several areas of science and engineering
We address the question of the asymptotic behavior of (1.1) under new general hypotheses for the perturbation functions
There are three big approaches to study the problem of asymptotic behavior of solutions for scalar linear differential equations of Poincaré type: the analytic theory, the nonanalytic theory and the scalar method
Summary
Linear fourth-order differential equations appear as the most basic mathematical models in several areas of science and engineering. Some landmarks in the analysis of the asymptotic behavior in linear ordinary differential equations are given by the works of Poincaré [30], Perron [25], Levinson [23], Hartman–Wintner [20] and Harris and Lutz [17, 18]. There are three big approaches to study the problem of asymptotic behavior of solutions for scalar linear differential equations of Poincaré type: the analytic theory, the nonanalytic theory and the scalar method. In relation to the nonanalytic theory, we know that the methods are procedures that consist of two main steps: first, a change of variable to transform the scalar perturbed linear differential equation in a system of first order of Poincaré type and a diagonalization process (for further details, consult [6, 10, 12, 24]). The results for the original problem are derived by analyzing the asymptotic behavior of this nonlinear equation
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have