在解决三角求值问题中,学生往往出现错解、漏解、增解甚至无从下手。原因是对题设条件理解不够深刻,不善于分析题设条件与结论中的角的相互关系,特别是对角的范围未充分注意。下面以例题说明上述问题。 In solving the problem of trigonometric evaluation, students tend to misunderstand, misunderstood, increase solutions and even have no way to start. The reason is that the understanding of the conditions for the title is not profound enough, and it is not good at analyzing the interrelationships between the conditions of the title and the corners of the conclusion. In particular, the range of diagonal angles is not paid enough attention. The following example illustrates the above problem.