Question

已知函數(shù)y=f(x+1)是偶函數(shù)，則函數(shù)y=f(2x)的圖像的對(duì)稱軸是(    )

A．x=l            B．x=-1           C．x=            D．x=-

Answer 1

C 

解析：本題考查函數(shù)圖像變換的應(yīng)用，本題也可通過舉特例的方法解答，即舉出滿足條件的函數(shù)y=f(x+1)再去解答亦可；據(jù)題意若函數(shù)y=f(x+1)為偶函數(shù)，故其圖像關(guān)于y軸對(duì)稱，則將其圖像向右平移1個(gè)單位即得函數(shù)y=f(x+1-1)=f(x)的圖像，即相應(yīng)的函數(shù)y=f(x)的圖像關(guān)于直線x=1對(duì)稱，再將橫坐標(biāo)變?yōu)樵瓉淼?SUB>，即得函數(shù)y=f(2x)的圖像，則相應(yīng)的函數(shù)的圖像關(guān)于直線x=對(duì)稱．