∵y=(log2(x)-2)*(log2(x)-1)/2（1）∴x=4^(2/3)=2^(4/3) y=(4/3-2)*(4/3-1)/2=-1/9(2)t=log2(x),∴y=(t-2)*(t-1)/2=(t^2-3t+2)/2(3)∵t=log2(x),∴t∈R∵y=(t-2)*(t-1)/2=(t^2-3t+2)/2=(t-3/2)^2/2-1/8∴ymin=-1/8...