解题方法
1 . 已知单调递增的等差数列
满足
,且
是
和
的等比中项,令
,则数列
的前100项和
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f65fc200f10b97588a0c9896277c9c64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/216876de04325fd250c38c485cbc34b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f329b217e1051b23f0d61023cdc6e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50f3d1b22d630bc1a295b94e8f94d2f3.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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2 . 已知圆
和点
,若过点
的5条弦的长度构成一个等差数列,则该数列公差的最大值是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc913bc204342a3c2e9d80d13078fb8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea24674c37fad354909efce890a94918.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
A.![]() | B.![]() | C.1 | D.2 |
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解题方法
3 . 已知数列
各项均为正数,
的前n项和为
,从①
,
;②
,这两个条件中任选一个,解决下面两个问题.(如果两个都选择的按第一个给分.)
(1)求数列
的通项公式;
(2)数列
为等比数列,满足
,
,数列
满足
,求
的前n项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.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/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14e056de2904d575b1ceda531ce6b0dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2d00dc5a6dd98808d33ea8d8f1c2da.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c968ef8f37cbc55d57380015e0229f77.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b73dff04e31174a03aa2a1a27a970eb0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5a3142edf5c4c0da42010fbbd78a099.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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4 .
为等差数列
的前
项和,已知
,
(1)求数列
的通项公式;
(2)当
取什么值时,数列
的前
项和有最小值,最小值是多少?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](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/01227530e9488cfcaf85c1db46f049e1.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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5 . 等差数列
的前
项和为
,则( )
![](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/624ca995c3095ac6ffd1a7d0d3acf2ed.png)
A.![]() | B.![]() |
C.![]() | D.当![]() ![]() |
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6 . 已知在等差数列
中,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76aef4cdcb5af742ce28003b7b6c8c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f110d93bbbcb9e2f3abc60b7388309a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7999465d0e871febde66296a0cbf058c.png)
A.3 | B.4 | C.5 | D.6 |
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解题方法
7 . 已知各项均为正数的数列
,其前
项和为
.数列
为等差数列且满足
,
,数列
满足
,求解下列问题:
(1)求数列
的通项公式及前
项和
;
(2)若对任意
,不等式
恒成立,求实数
的取值范围.
![](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/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1426751ddb78f554c9e2fec9521033c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/476741aadbb21b562ac1f1c99c9d4f8e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/893b6639a4f666c78923590b8bcce1f2.png)
(1)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)
(2)若对任意
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a37a59558292ad6b3d0978bfd7484990.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26e747b29dd43d669b39915527c9f571.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
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8 . 已知数列
、
满足
,
,其中
是等差数列,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b92cb5df2f912f155cf12dae0b30c1e9.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/010baf415f792018ad9abd752e37b983.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a37a59558292ad6b3d0978bfd7484990.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b61a41b7c5f96eeb0de11b6273b523a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b92cb5df2f912f155cf12dae0b30c1e9.png)
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解题方法
9 . 现有
枚硬币
. 对于每个
,硬币
是有偏向的,即向上抛出后,它落下时正面朝上的概率为
.
(1)将
这2枚硬币抛起,设落下时正面朝上的硬币个数为
,求
的分布列及数学期望
;
(2)将这
枚硬币抛起,求落下时正面朝上的硬币个数为奇数的概率.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9eb96e16163258d34b305c967766f438.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9859b14ed91b6b80a0b24edeadb43578.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a94555857a26590865f337f8c4a93c37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c55a495908bbc399791192f358b8344f.png)
(1)将
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21e9feabc99f62ee569b460e61526e2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5bf3baba074e8aeb6f3ea117865bbd1b.png)
(2)将这
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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解题方法
10 . 已知数列
满足
,
,若
,则n等于( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6065aaa8f3f103d1bc960da8318ce35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea28b47fd7cf5302e959c61ffdbdd6d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f53108a6fc6c9a31d59afd43f34ba0cb.png)
A.3 | B.4 | C.5 | D.6 |
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