已知定義域為

的二次函數(shù)
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的最小值為
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且

,直線
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被

的圖像截得的弦長為

,數(shù)列

滿足
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,
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
,設(shè)
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求
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的最值及相應的
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由已知可得
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
,由
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得
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所以
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,即
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,所以

,
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由

得

由

得
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,所以
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,即
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所以
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,即
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,且

,所以

,
所以

,


設(shè)

,則


所以當

時,



即

時,

有最小值

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
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
且
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(1) 證明:

;
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an與

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
,對一切

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
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
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

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
是等比數(shù)列;

(Ⅱ)把數(shù)列

中所有項按如圖所示的規(guī)律排成一個三角形
數(shù)表,當

時,求第

行各數(shù)的和;
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
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
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
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
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
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
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
中,點

在直線

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
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
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
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
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
是等差數(shù)列,

,則過點

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
滿足

成等比數(shù)列,

項和,則
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A.2 | B.3 | C. | D.不存在 |
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
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
項的積不小于
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