(本小題滿分14分)
(Ⅰ)已知

,

,求

的最小值。
(Ⅱ)已知

,求證:

。
解:(Ⅰ)

…… 5分
當且僅當

時取等號, 故

的最小值是

…… 7分
(Ⅱ)證明:∵

∴

…12分
∴

……… 14分
練習冊系列答案
相關習題
科目:高中數(shù)學
來源:不詳
題型:單選題
不等式

(其中

)對任意實數(shù)x恒成立,則實數(shù)
a的取值范圍為( )
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:單選題
若p、q、m是三個正數(shù),且q<100,現(xiàn)把m增加p%,再把所得結果減少q%,這
樣所得的數(shù)仍大于m,那么必須且只需 ( )
A.p>

B

.p>

C.p>

D.

p>q
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:單選題
若實數(shù)
a,
b滿足
a+
b=2,則3
a+3
b的最小值是( )
A.18 | B.6 | C.2 | D.3 |
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:解答題

(本題10分)
已知函數(shù)f(x)=
ax+2,不等式

<6的解集為

,試求不等式

≤1的解集.
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:單選題
若

,且

,則下列不等式一定成立的是 ( )
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:解答題
(本

小題滿分13分)
(1)解關于x的不等式

;
(2)記(1)中不等式的解集為A,函

數(shù)

的定義域為B.若

,求實數(shù)a的取值范圍.
查看答案和解析>>