一、将军饮马问题例1如图1,古希腊一位将军要从A地出发到河边l去饮马,然后再回到驻地B.问怎样选择饮马地点,才能使路程最短?解析:在河边饮马的地点有许多处,现在的问题是怎样找出使两条线段长度之和为最短的那个点来.在图上作点B关于河边l的对称点B′,连接AB′,交河边l于P,那么点P就是题目所求的饮马地点.因为BP=B′P,AP+BP=AP+PB′= First, the general problem of drinking horses 1 As shown in Figure 1, a Greek general from the departure point to the river l go to drink horses, and then back to the resident B. ask how to choose places to drink, in order to make the shortest possible distance? : There are many places for drinking a horse at a river, and the question now is how to find the point that minimizes the sum of the lengths of the two lines. AB ’, cross the river l at P, then the point P is the title of the request of the horse because BP = B’P, AP + BP = AP + PB’ =