函数单调性的应用一、求参量的取值范围例1已知函数f(x)=x2+4ax+6.(1)若函数f(x)在[2,+∞)上是增函数,求实数a的取值范围;(2)若函数f(x)的增区间是[2,+∞),求实数a的取值范围.解析(1)由于函数f(x)在[2,+∞)上是增函数,所以有-2a≤2,解得a≥-1.(2)由于函数f(x)的增区间是[2,+∞) Application of Function Monotonicity 1. Range of Values ​​of Finding Parameters Example 1 Known function f(x)=x2+4ax+6. (1) If the function f(x) is an increasing function on [2,+∞), Find the value range of real number a; (2) If the increment interval of function f(x) is [2, +∞), find the range of values ​​of real number a. Parse (1) Since function f(x) is in [2, +∞) is an increasing function, so there is -2a≤2, and the solution is a≥-1. (2) Since the increment interval of the function f(x) is [2,+∞)