“恒成立”与“存在性”经常与求参数的范围联系在一起,这两类问题常涉及到函数的图象和性质,渗透着换元、化归、数形结合、函数与方程等思想方法。这两类问题具有一定的共性,同时也有本质的区别,不能一律按恒成立问题解决。一、恒成立问题的剖析涉及恒成立不等式中变量的取值范围问 “Constantly established ” and “Existence ” are often associated with the range of parameters, these two types of problems often involve the image and nature of the function, infiltration of exchange yuan, And equation and other methods of thinking. These two types of problems have certain commonalities, meanwhile, they also have essential differences that can not be solved consistently with the establishment of a permanent government. First, the analysis of the problem of the establishment of constant Involves constant value range of variables in the inequality asked