三角函数式的最值问题，是三角知识应用方面的重要内容很多生活实际中的问题，常能归结为三角式的最值问题但如何求三角函数式的最值常使学生感到困难，其困难不在于单元知识的欠缺，而在于思想方法的运用上。由于这类问题常需要经过一类特殊的变形过程，而且无常规可循，学生 The problem of the trigonometric function is the most important aspect of the application of the triangular knowledge. Many problems in the practical life, often can be attributed to the triangular value problem, but how to find the most value of the trigonometric function often makes students feel difficult and difficult. It does not lie in the lack of knowledge in the unit, but in the use of ideas and methods. Because such problems often require a special kind of deformation process, and no routines can be followed, students