圆锥曲线有许多性质，已为人们所熟悉，对其他性质的讨论仍然吸引着广大的数学爱好者．笔者在教学中发现圆锥曲线的又一性质，现把它介绍如下．定理１设椭圆ｘ２ａ２＋ｙ２ｂ２＝１（ａ＞ｂ＞０），两焦点为Ｆ１（－Ｃ，０），Ｆ２（Ｃ，０）．点Ｑ为椭圆上除顶点外的任意... Conic curves have many properties and are familiar to people. The discussion of other properties still attracts a large number of math enthusiasts. The author found another characteristic of the conic section in teaching. Now it is introduced as follows. Theorem 1 sets the ellipse x2a2+y2b2=1 (a>b>0), and the two focuses are F1(-C,0) and F2(C,0). Point Q is an arbitrary point on the ellipse except the vertex...