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科目:高中數(shù)學
來源:不詳
題型:解答題
(12分)已知等比數(shù)列{a
n}的前n項和為S
n="3" · 2
n-3。
(1)求a
1、a
2的值及數(shù)列{a
n}的通項公式;
(2)設b
n=

,求數(shù)列{b
n}的前n項和T
n。
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科目:高中數(shù)學
來源:不詳
題型:單選題
ABCD-A
1B
1C
1D
1單位正方體,黑白兩個螞蟻從點A出發(fā)沿棱向前爬行,每走完一條棱稱為“走完一段”。白螞蟻爬地的路線是AA
1→A
1D
1→……,黑螞蟻爬行的路線是AB→BB
1→……,它們都遵循如下規(guī)則:所爬行的第

與第

段所在直線必須是異面直線(其中

是自然數(shù))。設白,黑螞蟻都走完2011段后各停止在正方體的某個頂點處,這時黑,白兩螞蟻的距離是( )
A.1 | B. | C. | D.0 |
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科目:高中數(shù)學
來源:不詳
題型:解答題
(本小題滿分13分)
已知數(shù)列

的前n項和

與通項

之間滿足關系

(I)求數(shù)列

的通項公式;
(II)設

求

(III)若

,求

的前n項和

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科目:高中數(shù)學
來源:不詳
題型:解答題
(12分)設



,若將

適當排序后可構成公差為1的等差數(shù)列

的前三項.
(Ⅰ)求


的值及

的通項公式;
(Ⅱ

)記函數(shù)

的圖象在

軸上截得的線段長為

,設

,求

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科目:高中數(shù)學
來源:不詳
題型:解答題
(本小題滿分14分)
將數(shù)列

中的所有項按每一行比上一行多一項的規(guī)則排成如下數(shù)表

:




………………………
記表中的第一列數(shù)

構成的數(shù)列為

,

.

為數(shù)列

的前

項和,且滿足

.
(1)證明:

;
(2)求數(shù)列

的通項公式;
(3)上表中,若從第三行起,每一行中的數(shù)按從左到右的順序均構成等比數(shù)列,且公比為同一個正數(shù).當

時,求上表中第

行所有項的和.
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科目:高中數(shù)學
來源:不詳
題型:填空題
等差數(shù)列{

}中,

,


,則此

數(shù)列的前15項之和是
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科目:高中數(shù)學
來源:不詳
題型:填空題
已知數(shù)列{a
n}的前n項和是

, 則數(shù)列的通項a
n=
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