在解含参数的不等式恒成立问题时,需要理清思路,分清层次,找准方法,如果直接求解较繁,可以转变角度,变换思维,就会有“柳暗花明又一村”的感觉,下面通过几个实例来说明含参不等式恒成立问题的解法.1策略一:改变主变元,构造新函数例1设实数a∈[-1,3],函数f(x)=x2-(a+3)x+2a,当f( When solving the inequality with parametric constants, we need to sort out the way of thinking, distinguish the layers and identify the methods. If we solve the problem more directly, we can change the angle and change the thinking. Then we will have the feeling of " A few examples are given to illustrate the solution to the problem of constitutive invariant inequalities.1 Strategy 1: Changing the main argument and constructing a new function Example 1 Let the real number a∈ [-1,3] and the function f (x) = x2- (a + 3) x + 2a, when f (