一、求函数的零点求函数的零点常以号生熟悉的二次函数结合函数的性质来命题,解答过程渗透着函数与方程、分类讨论等思想方法.例1已知f(x)是定义在R上的奇函数,当x≥O时,f(x)=x~2-3~x,则函数g(x)=f(x)-x+3的零点的集合为A.{1,3)B.{-3,-1,-1,3}C.{2-7(1/2),1,3}D.{-2-、7(1/2),1,3} First, find the zero point of the function Find the zero point of the function often familiar with the number of quadratic functions combined with the nature of the function to proposition, the solution process infiltration of functions and equations, classification and other ideas and methods .First known f (x) is the definition When x (x) = x ~ 2-3 ~ x, the set of zero points of the function g (x) = f (x) -x + 3 is A. {1 {- 3, -1, -1,3} C. {2-7 (1/2), 1,3} D. {- 2-, 7 (1/2), 1,3 }