求函数的值域是函数一章的重要问题,也是高考命题的热点.但在现行教材中没有举例说明它的求法,因而探讨求函数值域的方法无疑是十分必要的.那么怎样求函数的值域呢? 一、观察法有关基本函数的值域教材中已给出,通过观察,由这些函数的值域及不等式的性质,直接 Finding the value range of a function is an important issue in the function chapter and is also a hot topic of the college entrance examination proposition. However, in the current textbook, there is no example to illustrate its method of seeking. Therefore, it is undoubtedly necessary to explore the method of finding the value range of the function. Then how to find the function What is the value range? First, the observation method has been given in the value domain textbook on basic functions. By observing the value of the range and inequality of these functions,