平面向量的数量积是平面向量的核心内容,也是高考考查的热点内容.平面向量的数量积分坐标形式与几何形式两种.利用这两种形式及相关的性质,我们不仅可以解决平面向量的长度、角度、垂直等问题,还可以解决一些函数的最值问题,往往可以收到化繁为简、化难为易的效果.下面举例说明平面向量数量积性质的妙用.证明两向量的垂直问题判断两向量垂直的依据:①若a与b为非零向 The quantity product of plane vector is the core content of plane vector and also the hot content of college entrance examination.Planar vector quantity is two kinds of integral coordinate forms and geometric forms.Using these two forms and related properties we can not only solve the length of plane vector , Angle, vertical and so on, but also can solve the most value problems of some functions, and often can receive the effect of simplifying and simplifying the problem.Examples are given below to illustrate the magical effect of the property of the quantity vector of a plane vector.It is proved that the vertical problem of two vectors is judged Vertical basis of two vectors: ① If a and b are non-zero