y=(1/4)^-|x|的值域是 y=(1/3)^x2-x的单调递减区间是
问题描述：
y=(1/4)^-|x|的值域是 y=(1/3)^x2-x的单调递减区间是
答
y=(1/4)^-|x|=4^|x|
|x|>=0,y>=1
y=(1/3)^(x^2-x)
=(1/3)^[(x-1/2)^2-1/4]
=3^[1/4-(x-1/2)^2]
x>1/2单调递减