Question

三個數(shù)7^0.2，0.2⁷，ln0.2從大到小的順序是

A．70.2，0.27，ln0.2	B．70.2，ln0.2，0.27
C．0.27，ln0.2，70.2	D．ln0.2，70.2，0.27

Answer 1

A.

解析試題分析：7^0.2>7⁰="1," 0<0.2⁷<0.2⁰="1," ln0.2<lni=0,所以從大到小的順序是7^0.2，0.2⁷，ln0.2。
考點：本題考查指數(shù)函數(shù)、對數(shù)函數(shù)、冪函數(shù)的單調(diào)性。
點評：利用指數(shù)函數(shù)、對數(shù)函數(shù)的單調(diào)性比較大小，一般要取中間值，常用的中間值為0和1.