问题
解答题
已知x满足:2(log
|
答案
∵2(log
x)2+7log1 2
x+3≤0,∴1 2
≤log2x≤3.1 2
∵求f(x)=(log2
)•(log2x 2
)=(log2x-1)(log2x-2)=(log2x)2-3log2x+2,x 4
∴f(x)=(log2x-
)2-3 2
,1 4
∴f(x)max=f(x)
=2,f(x)min=f(x)log2x=3
=-log2x= 3 2
.1 4
故求f(x)=(log2
)•(log2x 2
)的最大值是2,最小值是-x 4
.1 4