求函数的值域是中学数学的一个重要内容,它与求函数的最值有着密切联系,学生在解这类问题时,常会出现这样或那样的错误,有些错误是容易发现的,而有些错误则往往很隐蔽。下面举例剖析如下。 Finding the value range of a function is an important part of high school mathematics. It is closely related to the function’s maximum value. When students solve such problems, they often have one or more mistakes. Some errors are easy to find, while others are wrong. It is often hidden. The following example is analyzed as follows.