空间角等于投影角的图解

Geometrical Proof of An Angle in Space Being Equal to Two Projecting

利用画法几何的方法,论证一般位置空间角等于两个投影角,通过推导得出简单的图解式.本文所用方法仅局限于画法几何及简单的形数结合,且可以推广应用于解决其他有一定难度的有关问题.

In this paper,it is proved by deseriptive geometry that an angle inspace generally equals to two projecting angles.A simple method combiningdeseriptive geometry with analylical geometry to deal with this problom isproposed here.This approach is simple but useful It can also be generalizedto treat other more difficult problems concerned.