兩數(shù)
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與
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的等比中項是 ( )
兩數(shù)的等比中項為
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,故選D
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科目:高中數(shù)學
來源:不詳
題型:單選題
等比數(shù)列

的各項均為正數(shù),且
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,則
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().
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科目:高中數(shù)學
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題型:解答題
等比數(shù)列
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中,已知
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1)求數(shù)列
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的通項
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2)若等差數(shù)列

,

,求數(shù)列

前n項和
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,并求
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最大值
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科目:高中數(shù)學
來源:不詳
題型:解答題
已數(shù)列
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滿足
a1 = 1,
a2 = 3,
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,

.
(1) 證明:數(shù)列

為等比數(shù)列;
(2) 求數(shù)列

的通項公式;
(3)
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,

的前
n項和為
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,求證
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.
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科目:高中數(shù)學
來源:不詳
題型:解答題
等比數(shù)列

中,公比

,數(shù)列的前n項和為

,若

,求數(shù)列

的通項公式。
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科目:高中數(shù)學
來源:不詳
題型:解答題
已知等比數(shù)列{
xn}的各項為不等于1的正數(shù),數(shù)列{
yn}滿足

=2(
a>0,且
a≠1),設
y3="18,"
y6=12.
(1)數(shù)列{
yn}的前多少項和最大,最大值為多少?
(2)試判斷是否存在自然數(shù)M,使得當
n>M時,
xn>1恒成立,若存在,求出相應的M;若不存在,請說明理由;
(3)令


試比較

的大小.
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科目:高中數(shù)學
來源:不詳
題型:填空題
設

成等比數(shù)列,其公比為2,則

的值為
;
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科目:高中數(shù)學
來源:不詳
題型:填空題
(文)已知無窮等比數(shù)列中的首項

,各項的和
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,則 公比q=_______________
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