相传 ,古希腊亚历山大里亚城有一位精通数学和物理的学者 ,名叫海伦 .有一天一位将军专程拜访海伦 ,求教一个百思不得其解的问题 :如图 1所示 ,从A地出发到笔直的河岸去饮马 ,然后再去B地 ,走哪一条路线最短呢 ?这个问题后来就被称为平面几何中的“将军饮马”问题 .图 1当时海 According to legend, in the ancient Greek city of Alexandria, there was a scholar who was fluent in mathematics and physics, named Helen. One day a general visited Helen and asked a question that was beyond our means: as shown in Figure 1, starting from A. Go straight to the river bank to drink horses, and then go to B, which route to take the shortest? This problem was later known as the “General to drink horses” problem in the plane geometry. Figure 1 was the sea