论文部分内容阅读
在解析几何中,对称是一种常见的关系,在直线方程学习结束时,我们总结对称问题,对提升用坐标法处理几何问题,拓宽解题思路,巩固并灵活运用所学知识,有很大帮助. 对称关系主要分中心对称和轴对称两类. 一、中心对称(1)点关于点对称例1已知点A(5,8),点B(4,1),试求点A关于点B的对称点A’的坐标. (方法一)可先设出点A’(x0,y0),然后根据|AB|=|BC|得到一个方程,再由k_(AB)k_(A’B)得到第二个方程,两方程联立可求解. (方法二)可根据B点是A、A’两点的中点,利用中点坐标公式求出.
In analytical geometry, symmetry is a common relationship. At the end of the learning of linear equations, we summarize the symmetry problem, enhance the use of coordinate methods to deal with geometric problems, broaden the problem-solving ideas, and consolidate and flexibly use what we have learned. Help. The symmetry relationship is mainly divided into two types: center symmetry and axisymmetric. A. Center symmetry (1) Points About point symmetry Example 1 Known points A(5,8), Point B(4,1), Try point A About The coordinates of point B’s symmetry point A’. (Method 1) The point A’ (x0, y0) can be set first, and then an equation can be obtained from |AB|=|BC| and then k_(AB)k_(A’ B) Get the second equation, the two equations can be solved simultaneously. (Method 2) can be found by using the midpoint coordinate formula according to the midpoint of the two points A and A’.