最值问题是近几年各地中考的热点,也是许多学生感觉比较棘手的问题.实际上,仔细分析,解决此类问题仍有规律可循,就线段的最大或最小而言,不外两种情形:(1)一动一定;(2)两动.解题的方法就是:分析动点的特征,怎么动,在哪里动?下面举例分析.例1如图1,△ABC、△EFG均是边长为2的等边三角形,点D是边BC、EF的中点,直线AG、FC相交于点M.当△EFG绕点D旋转时,线段BM长的最小值是() In fact, careful analysis and solution to such problems are still followed in the law. In terms of the maximum or minimum length of the line segment, there are only two kinds of problems Case: (1) a certain move; (2) two moving. The solution is: the characteristics of moving point analysis, how to move, where to move? The following example analysis. Example 1 △ ABC, △ EFG are The equilateral triangle of side length 2, point D is the midpoint of the edges BC, EF, and the straight lines AG, FC intersect at point M. The minimum value of the line length BM when (EFG) rotates around point D is ()