正弦定理、余弦定理都是揭示三角形边角之间数量关系的重要定理,要求能够运用正余弦定理解决一些简单的三角形度量问题.学了正、余弦定理后,不少同学为判断三角形的解的个数而烦恼,当三角形中已知两边和其中一边的对角时,可能出现一解、二解、无解等情况,虽然书上也有相应的方法,可是一些同学茫然依旧.近日在网上拜读了不少关于如何判断三角形的解的个数的文章,不少文章都认为在△ABC中,已知a,b和 Sine and cosine theorem are important theorems that reveal the relationship between the number of triangle corners and require that some simple triangle metric problems can be solved by the cosine and cosine theorem.After many positive and cosine theorems have been learned, The number of trouble, when the triangle is known on both sides and one side of the diagonal, there may be a solution, the solution, no solution, etc., although the book also has the corresponding method, but some students remain dazed.Recently online reading A lot of articles on how to determine the number of solutions to the triangle, many articles are that △ ABC, known a, b and