已知函数f(x)满足x>=4,则f(x）=(1/2)^x,当x

题目

已知函数f(x)满足x>=4,则f(x）=(1/2)^x,当x<4时,f(x)=f(x+1),则f(2+log2三对数）等于?

答案

2+log2(3)<4
而3+log2(3)>4
所以原式=f[2+log2(3)+1]
=f[3+log2(3)]
=1/2^[3+log2(3)]
=1/[2^3*2^log2(3)]
=1/(8*3)
=1/24