在平面解析几何中,有一类常见的轨迹问题,问题中动点的运动变化规律与两个定点相关联.关联程度有的较为简单直接,有的比较复杂曲折;所涉及的知识有多有少,其综合性可大可小;至于解答的难度,则深浅不一,而且,有不少问题蕴涵着丰富的数学思想方法,揭示了许多曲线的本质特征.因而,这类问 In plane analytic geometry, there is a common type of trajectory problem. The movement law of the moving point in the problem is related to two fixed points. The correlation degree is relatively simple and direct, some complex and tortuous; the knowledge involved is more or less. The comprehensiveness can be as large or as small as possible. As for the difficulty of the answer, there are different shades of depth. Moreover, there are many problems involving a wealth of mathematical thinking methods, revealing the essential characteristics of many curves. Therefore, such questions