余弦定理表达了三角形的边角关系,它内涵丰富,用途广泛,是中学数学中的重要定理之一,在教学过程中,教师除了要求学生熟记余弦定理及会用余弦定理解三角形外,还必须引导学生对余弦定理进行全方位的审视,多角度的探讨,以增强学生 The cosine theorem expresses the relationship between the corners of the triangle. It has a rich connotation and a wide range of uses. It is one of the important theorems in middle school mathematics. In addition to requiring the students to memorize the cosine theorem and use the cosine set to understand the triangle, Students must be guided to take a holistic view of the cosine theorem and explore it from multiple perspectives to enhance students