Question

若a，b是任意實(shí)數(shù)，且a＞b，則（　�。�

• A．a(chǎn)²＞b²
• B．

  b

  a

  ＜1
• C．lg（a-b）＞0
• D．2^a＞2^b

Answer 1

分析：利用指數(shù)函數(shù)f（x）=2^x在R上單調(diào)遞增，即可得出．

解答：解：∵函數(shù)f（x）=2^x在R上單調(diào)遞增，又a＞b，∴2^a＞2^b．
故選D．

點(diǎn)評(píng)：熟練掌握指數(shù)函數(shù)的單調(diào)性是解題的關(guān)鍵．