论文部分内容阅读
性质 设OA、OB、OC是空间中的三个向量 ,如图 1 ,则有 :( 1 ) (Ⅰ )OA+ BC =OC+ BA(Ⅱ )OA+ CB =OB+ CA(Ⅲ )OC +AB =OB +AC图 1(按一定顺序对棱所表示的向量之和相等 )( 2 )OA· BC + OB·CA +OC·AB =0(空间中的三个向量 ,每一个向量与其他两个向量的差的数量积的顺序之和等
The nature of OA, OB, OC is three vectors in space, as shown in Figure 1, then there are: (1) (I) OA + BC = OC + BA (II) OA + CB = OB + CA (III) OC + AB = OB + AC Figure 1 (The sum of the vectors represented by the edges in a certain order is equal) (2) OA · BC + OB · CA + OC · AB =0 (three vectors in space, each vector and two other vectors The sum of the order of the difference quantity product, etc.