1 . 设公差不为零的等差数列
的前n项和为
,若
,则
等于( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd0b498ac3ee7e370f9650d099aa397c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/980c77424642a2fc76a61c5cfaf8a967.png)
A.![]() | B.![]() | C.7 | D.14 |
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2020-03-10更新
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5卷引用:广西桂林市2019-2020学年高二上学期期末考试数学(理)试题
名校
解题方法
2 . 已知等差数列
中,若
,则此数列的前13项的和为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07404ab51f404f9411f79bd4f1fde654.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1df8ba47fc33f0c3b64e4411a8d709f1.png)
A.8 | B.9 | C.13 | D.12 |
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2020-03-10更新
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2卷引用:广西贺州市桂梧高中2019-2020学年高二上学期第一次月考数学试卷
3 . 等差数列
中,
,
.
(1)求通项公式
;
(2)若
,求
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8827c05075967f3c3569d31cb6b83919.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5c1344592c925b273f2cb9b9e47ebbb.png)
(1)求通项公式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efb8178fbfe116ec0eb61b25552a80f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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4 . 已知数列
中,
,
,则数列
的前
项和为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f087c4ce33b0755d7fd9c09e23df7e49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bf3da897eb73b729f66bb0d700775c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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2020-01-15更新
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2卷引用:2020届西大附中高三11月月考数学(文)试题
5 . 已知等差数列
的前n项和为
,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc4e70b360f988fdbd92300ab22c4613.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ac52eacb833a7a2d4c5d07340d2365d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc4e70b360f988fdbd92300ab22c4613.png)
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6 . 设等差数列
的前
项和为
,已知
.
(1)求
;
(2)求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6b69a9856a6cb1d9714407c7b1c23a8.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
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2019-12-09更新
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319次组卷
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2卷引用:江苏省宿迁市沭阳县2019-2020学年高二上学期期中数学试题
名校
7 . 设等差数列
满足
,
.
(1)求
的通项公式;
(2)求
的前
项和
及
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced4e381e8c3336848b8c436dbc584f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a499162d7bae04b117ea195a5124e38.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
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2019-10-25更新
|
466次组卷
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2卷引用:广西兴安县第二中学2020-2021学年高二上学期11月月考数学(文)试题
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8 . 已知数列
是等差数列,满足
,
,数列
是公比为3的等比数列,且
.
(Ⅰ)求数列
和
的通项公式;
(Ⅱ)求数列
的前n项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1928c254cfada1f75a5cd1e34db5a63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d046ec9d9aaac508a16462f2980ca18b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d39850521e5f5220161b0d3f5dc6543b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4995fa0403e013d888c0935ebfe15024.png)
(Ⅰ)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(Ⅱ)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
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2019-10-22更新
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955次组卷
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7卷引用:北京市朝阳区2019~2020学年高三上学期抽样检测数学试题
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9 . 设
为等差数列,
为数列
的前
项和,已知
,
,
为数列
的前
项和,则
的最大值为_________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/366dfedff1a1a96ec27650375b680059.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fa3a7ce62e7bf557d9e1bf77c8dac0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1705cd1b7eb5de318f6f140bbefaa16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
您最近一年使用:0次
10 . 已知数列
为递增的等比数列,
,
.
(Ⅰ)求数列
的通项公式;
(Ⅱ)记
,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78cb8d1b472bb1c0b09972ed73c2e0e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5de6e33f4455a10be635d52517a2df8b.png)
(Ⅰ)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(Ⅱ)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14e2a8417b428aa44fdeb3114119c023.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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2019-10-10更新
|
1199次组卷
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6卷引用:【校级联考】广西南宁市马山县金伦中学“4+ N”高中联合体2018-2019学年高二上学期期中考试数学(文)试题