【摘要】 本文讨论二次微分系统Ⅰ类方程ｄｘｄｔ＝ － ｙ＋ δｘ＋ ｌｘ２＋ ｍ ｘｙ＋ ｎｙ２，ｄｙｄｔ＝ ｘ 的极限环的存在性问题，纠正了文［１］中讨论当ｌ＝ ０ 时大范围内存在极限环的缺陷更多还原

【Abstract】 In this paper, the problem on the existence of limit cycles of Type Ⅰ equation of quadratic differential systems is discussed and an error on the existential limit cycles on large range when l=0 in [1] is corrected.更多还原