必修五第一章《解三角形》是在学习了必修二解析几何以及必修四三角函数和向量的基础上,进行研究斜三角形中边与角的关系的.主要是以正弦定理和余弦定理为主体,进行解三角形的应用,有些题目的考查则更侧重于已学知识的综合运用,及在多种解题方法中选择最优方法的思维训练.笔者在课上讲解一道课后练习题时,师生基于两个思想、四个角 Compulsory five The first chapter “solution triangle” is the study of the compulsory two analytic geometry and compulsory four triangle function and vector based on the study of oblique triangle in the corner and the relationship between the main sine and cosine theorem as the main body , The application of the triangle solution, the examination of some topics are more focused on the comprehensive use of knowledge has been learned, and a variety of problem-solving methods to choose the best method of thinking training.I explained in class after class practice questions, Teachers and students based on two ideas, four corners