利用积分直线研究二次系统极限环的唯一性

Study on the Uniqueness of Limit Cycle of the Quadratic System by Using Integral Straight Line

给出关于二次系统极限环唯一性的判别条件，所用的方法与常见的不同，它是先通过非奇异线性变换将所给系统变为新的二次系统，然后寻求新系统具有一条积分直线的条件，从而得到唯一性判别法．

In this paper,we consider the quadratic system A uniqueness criterion of limit cycle of (*) is obtained with the integral straight line, it is writen asTheorem Suppose the following two equations have common roots, then (* ) has at most one limit cycle.