f(x)={2x+3,(x<-1) 、x²,(-1≤x﹤1) 、x－1,(x≥1)} （1）畫出函數(shù)圖象?（2）f﹙x﹚＞1／4 ,x的取值范圍是?（3）f[f(x)]=1/4 ,x=?
(1)解析：
 

 
(2)解析：2x+3>1/4==>2x>-11/4==>-11/8<x<-1
X^2>1/4==>-1<=x<-1/2或1/2<x<1
x-1>1/4==>x>5/4
綜上：-11/8<x<-1/2或1/2<x<1或x>5/4
 
(3)解析：設(shè)t=f(x)
F(t)=1/4
解得t1=-11/8,t2=-1/2,t3=1/2,t4=5/4
2x+3=-11/8==>x=-35/16
X^2=-1/2,無解
X^2=1/2èx=-√2/2,x=√2/2
x-1=5/4==>x=9/4