設f(x)=x^2-x+k,log2(f(a))=2,f(log2(a))=k(a≠1), (1)求f(log2(x))的最小值及相應的x, (2)若f(log2(x))> f(1),且log2(f(x))< 2,求x的取值范圍。

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設f(x)=x^-x+k,log2(f(a))=2,f(log2(a))=k(a≠1), (1)求f(log2(x))的最小值及相應的x, (2)若f(log2(x))f(1),且log2(f(x))f(1)=2,即:[log2(x)]^-log2(x)+22log2(x)1∴02……②又由于log2(f(x))<2,且f(x)≥7/4即:f(x)<4,x^-x+2<4,∴-1