在教学活动中我体会到，对定义理解得深刻方能在应用时事半功倍，掌握定义的本质属性是学好数学的关键，下面以二次曲线定义为例，从以下两方面略谈一下用定义灵活解题．１　理解定义实质使“繁”变“简”图１例１　试证：自等轴双曲线上任意一点至两焦点的距离之积，等于该点 In the teaching activities, I realized that understanding the definitions is so deep that we can do more with less in the application. Mastering the essential attributes of definitions is the key to learning mathematics. The following uses the definition of the quadratic curve as an example. We will talk about using the definition flexibly in the following two aspects. Problem solving. 1 Understand the essence of the definition to make “brittleness” “simplified” Figure 1 Example 1 Testimonial: The product of the distance from any point on the isometric hyperbola to the two focal points is equal to this point