学完《解三角形》这章内容后,发现正余弦定理是解三角形的两大工具,它是勾股定理解直角三角形的工具的一种推广,并在测量距离、高度、长度等问题中有着广泛的应用.利用正余弦定理可以解一些三角形中的有关边与角的问题,实现边与角的转化.但如何灵活地 After learning the content of this chapter, we find that the cosine and cosine theorem are two major tools for solving triangles. It is a generalization of the Pythagorean theorem to solve the right-angled triangle and has some problems in the measurement of distance, height and length Wide range of applications. The use of sine and cosine theorem can be solved in some triangles on the edge and the angle of the problem, to achieve the transformation of edges and corners. But how flexible