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初中数学中,我们常会遇到一类“求线段之和最小值”问题.此类问题的解题方法灵活多变,许多同学觉得难以下手,找不到合适的切入口.下面笔者对这类问题进行分类梳理,谈谈如何巧用化折为直,妙解最值问题,希望对读者有一定帮助.一、两定一动例1(1)如图1,已知直线l的同侧有两个点A、B,在直线l上找一点P使PA+PB最小.方法如下:作点A(或者B)关于直线l的
In junior high school mathematics, we often encounter a class of “seeking minimum sum of line segments.” Problems such as flexible problem-solving methods, many students find it difficult to start, can not find the right cut entry. The classification of such issues combing, talk about how to use the fold straightforward, wonderful solution of the most value problems, I hope the reader will have some help .In two, a moving case 1 (1) As shown in Figure 1, Side of the two points A, B, find a little in the straight line l P PA + PB as follows: as point A (or B) on the straight line l