数学物理学报(英文版) ›› 1991, Vol. 11 ›› Issue (1): 65-71.
刘德明
Liu Deming
摘要: In this paper, we discuss the limit cycles of the system
dx/dt=y·[1+(A(x)]dy/dt=(-x+δy+a1x2+a2xy+a5x2y)[1+B(x)] (1)where A(x)=Σi=1naixi, B(x)=Σj=1m(Bjxj) and 1+B(x)>0. We prove that (1) possesses at most one limit cycle and give out the necessary and sufficient conditions of existence and uniqueness of limit cycles.