二面角是用来反映两个平面位置关系的一个重要数学概念,是现行教材中的重点和难点内容,也是历届高考的热点之一.本文从一道立体几何题就二面角的平面角常见的各种求法进行如下的探索与总结.问题在正方体ABCD-A1B1C1D1中,求二面角C1-D1B-C的大小.解法1直接法.借助题目给出的几何 Dihedral angle is an important mathematical concept used to reflect the relationship between the two planes, is the focus of the current textbook and difficult content, but also one of the hot spots in previous college entrance examination.This article from a three-dimensional geometric problems on the dihedral angle of the plane common In the cube ABCD-A1B1C1D1, find the size of the dihedral C1-D1B-C. Solution 1 Direct method. Given the title given by the geometry