一类函数值域问题探讨

Probe into the Value Region of one Function

函数的值域问题是中学的教学重点,学生学习的难点。其方法多,应用广泛,学生极难掌握。教师应注意启发学生思维,总结各种类型的函数值域求法,以帮助学生在复习中更准确、熟练地掌握。

The issue of value region of function is one key teaching point and one difficulty point for learning in middle school. Owing to many methods to solve it and wide application, it is hard for the students to grasp. The teacher should pay more attention to illumining the students to think about it, and summarize different methods to solve different kinds of function value region so as to help the students to grasp it correctly in their review study.