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 ,特别是对角的范围不注意 .本文通过例题说明上述问题 .一、注意考察轴线角这里所说的轴线角是指角的终边落在坐标轴 (ｘ轴或ｙ轴 In the solution to the problem of trigonometric evaluation, students often misunderstand, misunderstood or increase their solutions, and they have no way to start. The reason is that the conditions for setting up the questions are not profound enough, and they are not good at analyzing the interrelationships between the conditions of the questions and the angles in the conclusions. The range of diagonals does not pay attention. This article illustrates the above problem by way of example. First, pay attention to the axis angle. The axis angle here means that the end of the angle falls on the axis (x-axis or y-axis).