The Qualitative Research For A Class Of General System Of Liénard-type

This paper consists of three parts.It investigates the qualitative behaviors of the generalized system of Lienard typeIn the first chapter ,we discuss the local and global center and the oscillation of the system. We obtain a necessary condition for the local center and a necessary and sufficient condition for the global center and a sufficient condition for the oscillation of the system.In the second chaper,we discuss the boundedness of the system and give two sufficient conditions for the boundedness of a solution of the system . Some sufficient conditions,as well as some necessary and sufficient conditions for the boundedness of the system are given.In the third chapter ,we discuss the periodic solutions and the limit cycles of the system.We obtain six sufficient conditions for the limit cycles of the system.