(本小題滿分13分)設(shè)數(shù)列
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為等差數(shù)列,
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為
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的前
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項(xiàng)和,已知
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,
(1)求首項(xiàng)
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和公差
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;
(2)
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為數(shù)列
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的前
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項(xiàng)的和,求
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.
(1)
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;
(2)
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(1)設(shè)等差數(shù)列
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的公差為
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,則
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………………………………….7分
(2)
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………………………………….9分
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………………………………….11分
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數(shù)列
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是以
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為首項(xiàng),
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為公差的等差數(shù)列。
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�!�13分
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(本小題滿分12分)
設(shè)各項(xiàng)均為正數(shù)的數(shù)列
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的前n項(xiàng)和為
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,已知
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,數(shù)列
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是公差為
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的等差數(shù)列。
(1)求數(shù)列
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的通項(xiàng)公式(用
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表示);
(2)設(shè)
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為實(shí)數(shù),對(duì)滿足
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的任意正整數(shù)
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,不等式
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都成立。求證:
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的最大值為
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中,
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且
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的前
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項(xiàng)和,求證:
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滿足
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,
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,
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,則
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( )
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中,若
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是方程
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的兩根,那么
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的值為 ( )
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若數(shù)列
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中,
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,
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,則其通項(xiàng)公式
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=
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