直角三角形半角正切定理及应用

• 作 者: 何屹 党宇飞
• 机 构: 华中师大一附中,
• 出 处: 中学数学
• 发表日期: 2008年19期
• 关键词: 正切定理 角平分线 正弦定理 射影定理 半角 解题思路 华中师大 数量关系 直角边 理中

在几何题中,我们常常碰到有关三角形的问题,无论是在初中还是高中,直角三角形往往是我们研究的重点.有些定理我们耳熟能详,如直角三角形的勾股定理、射影定理等,但从这些定理中,我并没有发现有关直角三角形中边与角关系的定理.或许你会说有余弦和正弦定理,但我们在利用它们解决

In the geometry problem, we often encounter issues concerning the triangles. Whether in junior high schools or high schools, right angle triangles are often the focus of our research. Some of the theorems we are familiar with, such as right angle triangle Pythagorean theorem, projective theorem, etc., but from these In the theorem, I didn’t find a theorem about the relationship between edges and angles in right triangles. Maybe you would say that there are cosines and sine theorems, but we are using them to solve