论文部分内容阅读
一、引言在几何教学和研究中,人們时常要在一定平面上(如紙、黑板等)描繪一些直观图形,反映具体的或者想象的空間形体,帮助解决空間几何問題,以及可以归結为几何性貭的問題。学生在中学学习立体几何,教师有意識地指导他們掌握一些这方面的基本知識和技能,不仅有利于本門学科的学习,而且有利于以后接受解析几何、近世几何、工程制图、物貭結构等方面的科学技术知識。为区别起見,我們把具体存在于空間的形体或想象存在的形体(包括点、綫、面、体)叫做原形,反映原形的平面图形叫做图象,图象所在的平面叫做画面(也就是投影面,詳后)。画面上的图象,从视觉直观性的要求出发,似乎要画得逼真,观察时不要任何想象功夫,即非常直观;但
I. INTRODUCTION In the teaching and research of geometry, people often draw intuitionistic figures on a certain plane (such as paper, blackboard, etc.) to reflect concrete or imaginary spatial shapes, help solve spatial geometric problems, and can be attributed to geometry. Sexual problems. Students learn three-dimensional geometry in middle school. Teachers consciously guide them to acquire some basic knowledge and skills in this area. This is not only beneficial to the study of this subject, but also conducive to accepting analytical geometry, modern geometry, engineering drawing, and material structure in the future. Scientific and technical knowledge. For the sake of distinction, we refer to physical or imagined bodies (including points, lines, surfaces, and bodies) that exist in space as prototypes. The planes that reflect the original shape are called images. The plane in which the image is located is called the image (that is, Projection surface, detailed later). The images on the screen, starting from the requirements of visual intuition, seem to be realistic, without any imaginative observation, which is very intuitive; but