已知22
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/08/17 12:51:37
已知2
2 |
![已知22](/uploads/image/z/19203518-38-8.jpg?t=%E5%B7%B2%E7%9F%A522)
∵2
2≤x≤8,
3
2≤log2x≤3,
∴f(x)=log2
x
2•log2
x
4
=(log2x-1)(log2x-2)
=(log2x)2-3log2x+2
=(log2x-
3
2)2-
1
4
当log2x=3时,f(x)max=2
当log2x=
3
2时,f(x)min=-
1
4
2≤x≤8,
3
2≤log2x≤3,
∴f(x)=log2
x
2•log2
x
4
=(log2x-1)(log2x-2)
=(log2x)2-3log2x+2
=(log2x-
3
2)2-
1
4
当log2x=3时,f(x)max=2
当log2x=
3
2时,f(x)min=-
1
4