已知數(shù)列的前n項和
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,數(shù)列
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的前Ii項和
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①求數(shù)列
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和
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的
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通項公式;②設
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,求數(shù)列
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的前n項和
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的表達式
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科目:高中數(shù)學
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題型:解答題
設
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是公比大于1的等比數(shù)列,
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為數(shù)列
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的前n項和,已知
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,且
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成等差數(shù)列.
(I )求數(shù)列
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的通項公式
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;
(II)若
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,求和:
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數(shù)列
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的通項公式是
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,若前n項和為
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則
_____
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科目:高中數(shù)學
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在數(shù)列
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中,如果存在非零的常數(shù)
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,使得
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對于任意正整數(shù)
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均成立,那么就稱數(shù)列
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為周期數(shù)列,其中
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叫做數(shù)列
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的周期. 已知數(shù)列
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滿足
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,若
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,當數(shù)列
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的周期為
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時,則數(shù)列
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的前
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項的和
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為( )
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設
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是有窮數(shù)列{
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}的前n項和,定義:
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為數(shù)列{
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}的“Kisen”和.如果有99項的數(shù)列:
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…
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的“Kisen”和
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1000,則有100項的數(shù)列:1,
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…
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的“Kisen”和
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=
.
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科目:高中數(shù)學
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若
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成等比數(shù)列,則
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的最小值為 .
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科目:高中數(shù)學
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數(shù)列
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的通項
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,其前
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項和為
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,則
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="( " )
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