【摘要】 研究一类五次系统:dxdt=-y(ax2+bx+1)+Dx-lx3+mx5dydt=x(ax2+bx+1)我们计算了原点的焦点量,证明了原点至多为二阶细焦点,并且得到了原点是二阶细焦点时系统不存在极限环。更多还原

【Abstract】 The limit cycle and focal value for a class for plane fifth polynomial system,which is dxdt=-y(ax2+bx+1)+Dx-lx3+mx5dydt=x(ax2+bx+1),are discussed.The focal value of O(0,0) is obeained,and it is proved that the origin is a 2 order of fine focus at most.There are no any limit cycles when O(0,0) is a 2 order of fine focus.更多还原