在等差數(shù)列
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中,已知
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,
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,
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,則m為______________.
試題分析:設(shè)等差數(shù)列

的公差為
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,則
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解得
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由
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解得
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點(diǎn)評(píng):等差數(shù)列是高考中考查的重點(diǎn)數(shù)列,它的通項(xiàng)公式當(dāng)然是必不可少要考查的內(nèi)容,要熟練掌握,靈活應(yīng)用.
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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)已知數(shù)列
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滿足

,

(
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).
(Ⅰ)求數(shù)列
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的通項(xiàng)公式;
(Ⅱ)若數(shù)列
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滿足
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(
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),證明:數(shù)列

是等差數(shù)列;
(Ⅲ)證明:

(

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來源:不詳
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已知等差數(shù)列{a
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1=1,公差d>0,且第2項(xiàng),第5項(xiàng),第14項(xiàng)分別是等比數(shù)列{b
n}的第2項(xiàng),第3項(xiàng),第4項(xiàng).
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
的前n項(xiàng)和

(3)設(shè)數(shù)列{c
n}對(duì)任意自然數(shù)n,均有

,求c
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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,已知
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,那么

=
A.3 | B. | C.4 | D.5 |
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來源:不詳
題型:解答題
(本題滿分14分)
若等差數(shù)列

的前

項(xiàng)和為

,且滿足
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為常數(shù),則稱該數(shù)列為
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數(shù)列.
(1)判斷
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是否為
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數(shù)列?并說明理由;
(2)若首項(xiàng)為

且公差不為零的等差數(shù)列

為

數(shù)列,試求出該數(shù)列的通項(xiàng)公式;
(3)若首項(xiàng)為

,公差不為零且各項(xiàng)為正數(shù)的等差數(shù)列

為
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數(shù)列,正整數(shù)

滿足

,求
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的最小值
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來源:不詳
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(本題滿分14分)
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,若數(shù)列

,

滿足

,
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,
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,
(1)求

的關(guān)系,并求數(shù)列

的通項(xiàng)公式;
(2)記

, 若
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恒成立.求

的最小值.
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來源:不詳
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(文科題)(本小題12分)
(1)在等比數(shù)列{

}中,

=162,公比q=3,前n項(xiàng)和

=242,求首項(xiàng)

和項(xiàng)數(shù)n的值.
(2)已知

是數(shù)列

的前n項(xiàng)和,

,求

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來源:不詳
題型:單選題
等差數(shù)列
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中,已知前15項(xiàng)的和
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,則
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等于( )
A. | B.6 | C. | D.12 |
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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

的前

項(xiàng)和為

,

,且

.
(Ⅰ)求數(shù)列

的通項(xiàng)公式;
(Ⅱ)等差數(shù)列

的各項(xiàng)均為正數(shù),其前

項(xiàng)和為

,且

又


成等比數(shù)列,求

;
(III)求數(shù)列

的前

項(xiàng)和

.
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