随着数学竞赛内容向课本的靠近 ,解析几何中的圆锥曲线在高中数学联赛中的位置更加突出 .从1997年到 2 0 0 1年 ,联赛一试中都有三个左右的圆锥曲线问题 .这些题目源于课本而高于课本 ,背景深刻 ,综合性强 ,方法灵活 ,能有效地考查不同层次考生的思维品质 .例 1　 (2 0 0 0年全 As the contents of the mathematics competition approach the textbooks, the conic curves in analytical geometry have become more prominent in the high school math league. From 1997 to 2001, there were three or so conical curves in the league. Topics are derived from textbooks and textbooks. They have a deep background, strong comprehensiveness, and flexible methods. They can effectively examine the thinking qualities of candidates at different levels. Example 1 (2000)