Positive solutions of fourth-order Sturm–Liouville boundary value problems with changing sign nonlinearity

Abstract: In this paper, the existence of positive solutions is investigated for the following singular fourth-order Sturm–Liouville boundary value problem with changing sign nonlinearity: where is continuous, is continuous, is Lebesgue integrable. Without any nonnegative assumption on nonlinearity, by choosing a proper cone and creating an available integral operator, the existence of the positive solutions for the above singular Sturm–Liouville boundary value problem is established. Some examples are worked out to indicate the application of our main result. [Copyright &y& Elsevier]