论文部分内容阅读
有一道流行的题目[1]:如图1,五边形ABCDE中,点M、N、P、Q分别是AB、DE、AE、BC中点,K、L分别为PQ、MN的中点,图1则K L∥=14CD.文[1]为了配合向量的练习给出的是一个用向量的证明:证法1在平面上任取一点O(如图1),∵K、L分别为PQ、MN的中点,∴OK=12(OP+OQ),OL=12(OM+ON).而K L=OL
There is a popular topic [1]: As shown in Figure 1, in the pentagonal ABCDE, points M, N, P, and Q are the midpoints of AB, DE, AE, and BC, respectively, and K and L are the midpoints of PQ and MN, respectively. Fig. 1 KL∥=14CD. [1] The training given for coordination with vectors is given as a proof of vector: The proof method 1 takes a bit of O on the plane (as shown in Fig. 1), and K and L are PQ respectively. , MN’s midpoint, ∴OK=12 (OP+OQ), OL=12 (OM+ON). And KL=OL