向量既是代数的对象,又是几何的对象,它是沟通代数与几何的桥梁,体现了数形结合思想.利用平行四边形使向量的加减运算直观化,从而化解向量的抽象性,可快捷地把问题解决.笔者通过如下几个向量问题来展示如何利用平行四边形巧妙、灵活地解决向量问题.例1已知非零向量a,b的夹角为6 A vector is both an algebraic object and a geometric object. It is a bridge for communicating algebra and geometry, embodying the idea of ​​combining numbers and shapes. It uses a parallelogram to visualize the addition and subtraction of vectors, thereby resolving the abstractness of vectors and quickly Solve the problem. The author shows how to use the parallelogram to solve the vector problem in a clever and flexible way through the following vector problems. Example 1 Known non-zero vector a, b angle 6