【摘要】 用投影变换求解空间问题时,应用逆向思维方法与投影变换原理及多种作图方法灵活结合,逆向寻求结论成立、答案存在的充分必要条件,弄清逆向路径,可以解决某些用正向思维方法难以找到求解路径的空间题。更多还原

【Abstract】 This paper suggests that counter thinking and projection change together with various drawing methods could help to find out the full necessary conditions for the conclusion and answer,and that when the counter path is explored,it would be possible to solve some space questions that are difficult to deal with by the normal thinking method.更多还原