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轨迹问题是平面解析几何中非常重要的一类问题,在高考中经常出现。求轨迹方程的方法比较多,但从宏观上说不外乎两个途径:一是利用平面几何知识和圆锥曲线的定义,这类题目对计算的要求不高,主要考查观察、联想的能力;二是利用代数的方法通过消参数得出轨迹方程,计算、对式子的变形是解决问题的关键。一、定义法:运用有关曲线的定义求轨迹方程例1在△ABC中,BC=24,AC,AB上的两条中线长度之和为39,求△ABC的重心的
Trajectory problem is a very important kind of problem in plane analytic geometry, which often appears in college entrance examination. There are many ways to find the trajectory equation, but macroscopically no more than two ways: one is the use of plane geometry knowledge and the definition of conic curve, these questions do not have high computational requirements and mainly examine the ability of observation and association; The second is the use of algebraic method to determine the trajectory equation by eliminating parameters, calculation, the expression of the deformation is the key to solve the problem. First, the definition of law: the definition of the use of the curve to find the trajectory equation Example 1 In △ ABC, BC = 24, AC, AB on the length of the two lines and 39, seeking △ ABC center of gravity