平面向量是高中数学试验教材中新增的内容,它是个很好的工具,应用方面也很多.下面通过举例来说明向量知识在解题中的应用. 一、应用于解平面几何问题 例1 如图1 已知AC,CE 为正六边形ABCDEF的两条对角线,点M,N分别内分AC,CE且使AM:AC=CN:CE=r,如果B,M,N 三点共线,试求r的值. 解设CA=a,CE=e, Plane vector is a new addition to mathematics textbooks for high school students. It is a good tool and has many applications. The following examples illustrate the application of vector knowledge in solving problems. Figure 1 Known AC and CE are the two diagonals of the regular hexagon ABCDEF. Points M and N are divided into AC and CE respectively and AM:AC=CN:CE=r. If B,M,N are three points Line, try to find the value of r. Solve for CA=a,CE=e,