Existence Of Positive Solutions To Bvps Of Higher Order Differential Equations

This paper is concerned with the existence of positive solutions for bvps of several kinds of higher order differential equations. The main results are obtained by using Krasnoselskii's fixed point theorem in cones. These results extend some of the existing literature.This thesis of Master is composed of three chapters. Chapter 1 mainly considers the existence of positive solutions for bvps of the nonlinear higher order differential equationWe generalize some known results, and obtain some existence and nonexistence results.In chapter 2, based on chapter 1, we considers the existence of positive solutions of the higher order delay differential equationwith the boundary conditionsWe generalize the results in chapter 1.In chapter 3, we consider the existence of positive solutions for bvps of the higher order delay differential equation when g(t,u) is the superlinear function (it isn't considered in chapter 2). A sufficient and necessary condition is established. This result extends some of the existing literature.