含有自然对数函数的不等式恒成立,求参数取值范围问题,若用参数分离法将参数分离后,不等式的另外一边是一个超越函数,对该函数求导后往往仍然为一个超越函数,求其根常常难度很大.因此,命题人提供的参考答案通常是用分类讨论法来回避对超越函数的研究.而同学们往往不愿意分类讨论,却对参数分离法情有独钟,选择了参数分离法又因为超越函数难以 Inequality with natural logarithm function is always established, and the range of parameter value is found. If the parameters are separated by parametric separation method, the other side of the inequality is a transcendental function. After the derivation of the function, it is often still a transcendental function. The roots are often very difficult.Therefore, the propositional answers are usually provided by the method of classification to avoid the study of transcendental function.And students are often reluctant to categorize the discussion, but the preference for the separation of parameters, the choice of Parameter separation method and because of the beyond function is difficult