把數(shù)列
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的所有項按照從大到小的原則寫成如右圖所示的數(shù)表,其中的第
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行有
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個數(shù),第
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行的第
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個數(shù)(從左數(shù)起)記為
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則
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_____________.
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前9行共有
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個數(shù),所以
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是數(shù)列
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中的第1006項,即
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科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
(本小題滿分14分)
(理)已知數(shù)列{a
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中,a
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=5且a
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=3a
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(n≥2)
(1)求a
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的值.
(2)設(shè)b
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=
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,是否存在實數(shù)λ,使數(shù)列{b
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為等差數(shù)列,若存在請求其通項b
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,若不存在請說明理由.
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科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
用三段論證明: 通項公式
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的數(shù)列
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是等差數(shù)列.
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科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
設(shè)數(shù)列
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的前
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項和為
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,且
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,數(shù)列
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為等差數(shù)列,公差大于0,且
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是方程
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的兩個實根
(1) 求數(shù)列
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、
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的通項公式; (2) 若
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,求數(shù)列
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的前
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項和
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科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
數(shù)列
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滿足
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,若
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,則數(shù)列
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的第2010項
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的值為 ( )
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科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
(本小題滿分14分)
已知:有窮數(shù)列{a
n}共有2k項(整數(shù)k≥2 ),a
1="2" ,設(shè)該數(shù)列的前n項和為 S
n且滿足S
n+1=aS
n+2(n=1,2,…,2k-1),a>1.
(1)求{a
n}的通項公式;
(2)設(shè)b
n=log
2a
n,求{b
n}的前n項和T
n;
(3)設(shè)c
n=
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,若a=2
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,求滿足不等式
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+
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+…+
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+
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≥
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時k的最小值.
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科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
設(shè)
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是等差數(shù)列,
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,則過點
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的直線斜率為
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科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
在等差數(shù)列
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中,
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則其前11項的和
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( )
A.99 | B.198 | C. | D.128 |
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