Question

函數(shù)y=2^x與y=(

1

2

)x的圖象關(guān)于下列那種圖形對(duì)稱（　�。�

Answer 1

分析：把函數(shù)y=(

1

2

)x變形為y=2^-x，函數(shù)y=2^x與函數(shù)y=2^-x的圖象關(guān)于y軸對(duì)稱，由此可以得到正確答案．

解答：解：因?yàn)?span id="vuirr22" class="MathJye">y=(

1

2

)x=(2-1)x=2-x，
把函數(shù)y=2^x的自變量x換為-x得y=2^-x，
它們的圖象關(guān)于y軸對(duì)稱，
所以函數(shù)y=2^x與y=(

1

2

)x的圖象關(guān)于y軸對(duì)稱．
故選B．

點(diǎn)評(píng)：本題考查了指數(shù)函數(shù)的性質(zhì)，考查了函數(shù)圖象的對(duì)稱性，對(duì)于函數(shù)y=f（x）來(lái)說(shuō)，x換為-x，得到的圖象與原函數(shù)關(guān)于y軸對(duì)稱，y換為-y，得到的圖象與原函數(shù)圖象關(guān)于x軸對(duì)稱，此題是基礎(chǔ)題．