等差數(shù)列
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的前
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項和為
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,若
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,那么
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的值是 ( )
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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12分)
已知數(shù)列
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,
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,
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(Ⅰ)當
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為何值時,數(shù)列
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可以構成公差不為零的等差數(shù)列,并求其通項公式;
(Ⅱ)若
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,令
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,求數(shù)列
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的前
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項和
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。
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科目:高中數(shù)學
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設
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是等差數(shù)列,且滿足
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,若
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,給出下列命題:
(1)
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是一個等比數(shù)列; (2)
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; (3)
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; (4)
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; (5)
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.
其中真命題的個數(shù)是( )
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科目:高中數(shù)學
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題型:單選題
已知等差數(shù)列
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的通項公式為
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.則它的公差為( )
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科目:高中數(shù)學
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設
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是等差數(shù)列
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的前
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項和,
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,則
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的值為
A. | B.1 | C.2 | D.3 |
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科目:高中數(shù)學
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題型:填空題
在直角坐標平面中,已知點
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,
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,對平面上任意一點
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,記
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為
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關于
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的對稱點,
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為
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關于
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的對稱點,
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為
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關于
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的對稱點,
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為
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關于
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的對稱點,…,
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為
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關于
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的對稱點,
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為
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關于
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的對稱點,
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為
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關于
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的對稱點
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…。則
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=
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科目:高中數(shù)學
來源:不詳
題型:單選題
數(shù)列{a
n},a
1=
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,a
n=2-
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(n≥2)則a
2008等于 ( )
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