一、不等式与函数的综合题解决不等式与函数的综合题,要充分运用函数的单调性,注意函数的定义域,并结合函数的奇偶性、周期性一起进行分析与研究.【例1】已知定义域为(0,+∞)的函数(f x)满足:(1)x1时,(f x)0;(2)(f21)=1;(3)对任意的x,y∈(0,+∞),都有(f xy)=(f x)+(f y).解不 First, inequalities and functions of the comprehensive problem to solve inequalities and functions of the comprehensive problem, to make full use of the monotony of the function, pay attention to the function of the definition of the domain, combined with the function of the parity, periodic analysis and research together. [Example 1] A function (fx) that knows that the domain is (0,+∞) satisfies: (1) x1, (fx)0, (2) (f21)=1, (3) for any x,y∈ (0, +∞), there is (f xy) = (fx) + (fy). Solution is not