Question

（2002•上海）設(shè)a＞0，a≠1，則函數(shù)y=log_ax的反函數(shù)和函數(shù)y=log_a

1

x

的反函數(shù)的圖象關(guān)于（　�。�

A．x軸對(duì)稱

B．y軸對(duì)稱

C．y=x對(duì)稱

D．原點(diǎn)對(duì)稱

Answer 1

分析：先看原函數(shù)圖象的對(duì)稱性，再根據(jù)原函數(shù)與其反函數(shù)的對(duì)稱性，即可求反函數(shù)圖形的對(duì)稱軸．

解答：解：y=log_ax與y=log_a

1

x

=-log_ax關(guān)于y軸對(duì)稱，
則其反函數(shù)也關(guān)于y軸對(duì)稱．
故選B．

點(diǎn)評(píng)：本題考查反函數(shù)的對(duì)稱問(wèn)題，是基礎(chǔ)題．