Existence of positive periodic solution for the electron beam focusing system

In this paper, we study the mathematical model of electron beam focusing system where a>0,b?0 are constants, find conditions for the existence of positive π‐periodic solution of the above equation by using analytical method and comparison theory, and prove the existence of positive π‐periodic solution by the continuously dependent theory of initial value problem. Copyright © 2004 John Wiley & Sons, Ltd.