已知f(x)=log以a为底丨log以a为底x丨(0
问题描述：
已知f(x)=log以a为底丨log以a为底x丨(0
答
1）1/a>x>a且x不等于1 2）单调递减,设x1>x2,log以a为底|log以a为底x1|-log以a为底|log以a为底x2|=log以a为底[|log以a为底x1|/|log以a为底x2|]=log以a为底|log以x2为底x1|,因为x1>x2,0