試題分析:由數(shù)列前幾項易得:
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,
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.故選C.
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項求和(分組求和法)
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科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
已知數(shù)列{a
n}滿足:
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,
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,
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(Ⅰ)求
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,并求數(shù)列{a
n}通項公式;
(Ⅱ)記數(shù)列{a
n}前2n項和為
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,當(dāng)
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取最大值時,求
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的值.
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科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
已知等差數(shù)列
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的前n項和為
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,且
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,
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.
(1)求數(shù)列
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的通項
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;(2)設(shè)
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,求數(shù)列
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的前n項和
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.
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科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
已知正實數(shù)數(shù)列
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中,
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,則
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等于( )
A.16 | B.8 | C. | D.4 |
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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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的首項為
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,
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為等差數(shù)列且
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.若則
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,
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,則
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=( )
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科目:高中數(shù)學(xué)
來源:不詳
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某校甲、乙兩食堂2013年元月份的營業(yè)額相等,甲食堂的營業(yè)額逐月增加,并且每月增加值相同;乙食堂的營業(yè)額也逐月增加,且每月增加的百分率相同。已知2013年9月份兩食堂的營業(yè)額又相等,則2013年5月份營業(yè)額較高的是( )
A.甲 | B.乙 |
C.甲、乙營業(yè)額相等 | D.不能確定 |
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科目:高中數(shù)學(xué)
來源:不詳
題型:填空題
數(shù)列

是公差不為0的等差數(shù)列,且
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,則
.
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