摘要
利用旋转向量场理论得到Ⅲa=0 类二次系统 x =-y+δx+lx2 +mxy +ny2 y =x(1 +y) (n =- 1 ,0 <l<1 ) 。
By application of the theory of rotating vector field ,this paper obtains the sufficient conditions for limit circle of the second system of Ⅲ a=0 x=-y+x+lx 2+mxy+ny 2(n=-1,0<l<1) y=x(1+y), that exists in origin periphery.
出处
《洛阳大学学报》
2001年第4期13-15,共3页
Journal of Luoyang University
