解析几何中的定值问题一直是高考和竞赛中的热点问题之一,也是高中数学中的难点之一.事实上,对这类问题的解答还是有规律循的,其解题步骤仍可归纳为:一选,二求,三定值.具体操作程序如下:一选:选择参变量.需要证明为定值的量在通常情况下“照理”应该是个变量,它应该随某一个量的变化而变化,可选择这个量为参变量.二求:求出函数的解析式.即把需要证明为定值的量表示成关于上述参变量的函数(不妨称这 The problem of fixed value in the analysis of geometry has always been one of the hot issues in college entrance examination and competition, and also one of the difficulties in high school mathematics. In fact, the solution to this kind of problem still follows a regular pattern, and the solving steps can still be summarized As follows: one election, two seeking, three fixed value. The specific operating procedures are as follows: Select: Select parameters. Need to prove the amount of value In normal circumstances, “reasonable” should be a variable, it should be with a certain amount Second, find: Find the analytical function of the function, that is, the need to prove the value of the fixed value as a function of the above parameters (may wish to call this