教学背景介绍高三教学过程中,对含参的多变量函数的恒成立和存在性问题的解答时,我们常采用两种方案,方案一:对参数进行分类讨论,通过研究含参函数的单调性从而得出其最值,再代入计算;方案二:先进行变量分离,在对分离后的函数单调性研究得最值代入.事实上我们发现无论在平时的作业还是在诊断性测试中,如果学生用方案一则往往会讨论不全,而用变量分离则 Teaching background The third year of teaching process, the parametric multi-variable function containing the constant establishment and existence of the answer, we often use two programs, program one: the parameters of the classification discussion, by studying the monotonous function So as to get the most value, and then substituted into the calculation; Option two: the first variable separation, monotonicity of the function after the separation of the best value into. In fact, we found that in peacetime or in diagnostic tests, if Student programs often discuss incomplete, but the use of variable separation