解:因為

,則利用均值不等式和不等式的性質(zhì)得到結(jié)論,選A
練習(xí)冊系列答案
相關(guān)習(xí)題
科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
若

,則有( )
查看答案和解析>>
科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
(選修4-5)已知函數(shù)

,

(Ⅰ)當(dāng)

時,解不等式

;
(Ⅱ)若存在

,使得

成立,求實數(shù)

的取值范圍.
查看答案和解析>>
科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
若非零實數(shù)

滿足

,則( )
A.

B.
B.

D.

查看答案和解析>>
科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
若實數(shù)

滿足


.
試確定

的大小關(guān)系.
查看答案和解析>>
科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
已知三條直線

,

,

,三個平面

,

,

.下面四個命題中,正確的是()
查看答案和解析>>
科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
若

,則下列不等式恒成立的是 ( )
查看答案和解析>>
科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
設(shè)

,則下列不等式中

的是( )
查看答案和解析>>