论文部分内容阅读
如图,正方形AB-CD中,过点D作DP交AC于点M、交AB于点N、交CB的延长线于点P,若MN=1,PN=3,求DM的长.这道题引起我兴趣的是,求DM的长的时候,一定要用到相似三角形,而与DM边有关的任何一对相似三角形,它们的对应边至少有两个未知量,有的更多,所以用一对相似三角形对应边成比例的办法是求不出DM的长的.这就为解题增加了难度,当想到未知量较多时可用方程组解题的办法时,我的眼前一亮,我把题中所有的相似三角形都列出来,分成几
As shown in the figure, the square AB-CD, the point D for the DP AC AC at the point M, to AB at point N, to pay the extension of CB at point P, if MN = 1, PN = 3, find DM long. I am interested in the problem is that when seeking DM long time, we must use similar triangles, and the DM side of any pair of similar triangles, the corresponding edge of at least two unknowns, and some more, So using a pair of similar triangles corresponding to the side is proportional to the method is not to find the DM’s long.This is to increase the difficulty of solving problems, when you think of the unknown amount of equations can be used to solve the problem, I shines , I put all the similar questions in the triangle are listed, divided into several