【摘要】 <正> 在文献〔1〕里,作者曾推导出两个关系式: F(x,■)=F〔x,(-1)■〕 (1)(1)是用来求对称于x轴的极限环的代数方程的关系式。 F(x,■)=-F〔(-1)x,■〕 (2)(2)是用来求对称于x轴的极限环的代数方程的关系式。用同样的方法可推导出一个关系式更多还原

【Abstract】 In this paper, we merely consider the non-linear differential eq- uations of (??) (1) type. After the existence of the limit cycles of (1), which are symmetrical with respect to the origins, but asymmetrical with respect to both axes of coordinates on the phase plane, had been proved, two kinds of algebraic epuations of limit cycles may be obtained. As for the differential equations of (??) (2) type, the precise algebraic equations of limit cycles can be established. As for the differential equations of (??) (3) type, the only approximate algebraic equations of limit cycles can be established.更多还原