在有关二面角大小的计算中,常常碰到二面角的棱没在图形上出现的情况,这样增加了寻找二面角的平面角的难度,对这种“尖尖”二面角的求法,通常有两种策略:(1)通过图形的割补、平面延展等方法画出二面角的棱进而去找平面角;(2)不画出二面角的棱,直接通过转化的思想来求证二面角的 In the calculation of the dihedral angle, it is often encountered that the edges of the dihedral angle do not appear on the graph, which increases the difficulty of finding the plane angle of the dihedral angle, for such “spiky” dihedral angles. There are usually two strategies to solve the problem: (1) Draw dihedral angles and then find the plane angles by means of cutting, plane extension, etc.; (2) Do not draw edges with dihedral angles. To verify the dihedral