在高考复习中,有这么一类向量考题,它以平面几何中的点线关系为背景,以向量的数量积为测试平台,以考查学生的化归能力为目标.这种将向量的数量积问题转化为代数、三角、解几问题的解题方法,其思维量很大,运算要求很高,推理路径很长;其求解过程绕来绕去,难以把握转化的方向.笔者在研究中发现这类向量数量积的考题,有一个共同特点:它们都是共点向量或可化为共点向量的数量积,可以借用一个基本公式转化命题, In the college entrance examination review, there is such a vector test, which takes the geometric relationship between the dotted line in the background, the number of products as a test platform to test the ability of students to return as the goal of this quantity of the product of the product The problem is transformed into algebra, trigonometry, solution to several problems of the problem-solving method, which has a large amount of thinking, high computational requirements, reasoning path is very long; its solution process around, difficult to grasp the direction of conversion.I found in the study There is one thing in common with the test of the number of products in this kind of vector: all of them are common-point vectors or quantity products that can be transformed into common-point vectors, and can be transformed into propositions by borrowing a basic formula,