已知函数f(x)=(1/2)^x,x大于等于4,f(x+1),x小于4,
2+log2(3)<4
f(2+以2为底以3真数的对数)
=f(2+以2为底以3真数的对数+1)
=f(3+log2 3)
=(1/2)^(3+log2 3)
=(1/2)^3*(1/2)^(log2 3)
=1/8*(2^-1)^(log2 3)
=1/8*2^(-log2 3)
=1/8*2^(log2 3^-1)
=1/8*1/3
=1/24