因为 f(x) 奇函数,所以,当x∈(0,1) 时.
f(x)= -2^(-x)
log2(5)>log2(4)=2,
log2(5)<log2(8)=3,
所以, 0<log2(5)-2<1,
由f(x+2)=f(x)知,f(x)周期为2,
所以,f(log2(5))=f(log2(5)-2)
= -2^[-log2(5)+2]
= -{2^[log2(5)]}^(-1)·2^2
= -5^(-1) · 4
= -4/5
2