三角函数最值问题是三角函数基础知识的综合应用,是高考必考内容.如何使解题过程简洁明快,方法“活”且“巧”呢?不妨从以下三点出发:一观察、二定型、三解题.1.利用正、余弦函数的有界性(1)y=asinx+b或y=acosx+b型函数,利用三角函数的值域,须注意对字母的讨论.例1求函数y=2-3sinx的值域. The most important issue of trigonometry is the comprehensive application of the basic knowledge of trigonometry, is the content of the entrance exam .How to make the problem-solving process simple and neat, the method of “living ” and “clever ”? From the following three points: one Observe, two stereotypes, three problems.1.Using positive and cosine functions of the bounded (1) y = asinx + b or y = acosx + b type function, the use of trigonometric function range, pay attention to the discussion of letters Example 1 Find the function y = the range of 2-3 sinx.