On the existence of positive solutions of fourth-order ordinary differential equations

Abstract

Abstract We study the existence of positive rolutioru of the equations with either . We show the existence of at least one positive solution iff is either superlinear or sublinear by a simple application of a Fixed Point Theorem in cones. Keywords: fourth-order ordinary differential equationexistence positive solution *Department of Mathematics, Northwest N o d University, Lanzhou, Gansu 730070, China **Department of Mathematics, Michigan State University, East Lansing, MI 48824, USA. *Department of Mathematics, Northwest N o d University, Lanzhou, Gansu 730070, China **Department of Mathematics, Michigan State University, East Lansing, MI 48824, USA. Notes *Department of Mathematics, Northwest N o d University, Lanzhou, Gansu 730070, China **Department of Mathematics, Michigan State University, East Lansing, MI 48824, USA.