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解题方法
1 . 设数列
满足:①
;②所有项
;
③
.设集合
,将集合
中的元素的最小值记为
.换句话说,
是数列
中满足不等式
的所有项的项数的最小值.我们称数列
为数列
的伴随数列.例如,数列1,3,5的伴随数列为1,2,2,3,3.
(1)请写出数列1,5,7的伴随数列;
(2)设
,求数列
的伴随数列
的前30项之和;
(3)若数列
的前
项和
(其中
常数),求数列
的伴随数列
的前
项和
.
![](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/9b614e06663d93a618d95f416e35af54.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dd992f0b72c282959031890e58c7810.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a1290895db96907d5054c7cc8ab2f06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a0d7559d8dfa8236ca9d4b1853fbdec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f64696f60c533ad95dc7890eb902741.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f64696f60c533ad95dc7890eb902741.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63cad0f23354aa754ade482d849557fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)请写出数列1,5,7的伴随数列;
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbb2f1272b626e0fd5c79c1a91d48b07.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(3)若数列
![](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/7051ba2351ffb1a1900f931833054bac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62c320a0619c63a5b650a1a94c0a5679.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7e74be91bfe4bc209da7539dbf9b72c.png)
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名校
解题方法
2 . 某校团委对学生性别和喜欢短视频是否有关联进行了一次调查,其中被调查的男生、女生人数均为
,男生中喜欢短视频的人数占男生人数的
,女生中喜欢短视频的人数占女生人数的
.若有
的把握认为喜欢短视频和性别相关联,则
的最小值为________ .附
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00b6803cab3329586ed82bdf831db99e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf31876698721a199c7c53c6b320aa86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a363cc53497fdfac77b43f656424f973.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2187714e660234f0b72f2b47d3ea685a.png)
![]() | 0.05 | 0.01 |
![]() | 3.841 | 6.635 |
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3 . 某校开展“阳光体育节”活动,其中传统项目“定点踢足球”深受同学们喜爱.比赛规则为:甲、乙两人轮流进行足球定点踢球比赛(每人各踢一次为一轮),在相同的条件下,每轮甲、乙两人在同一位置,甲先踢,每人踢一次球,两人有1人命中,命中者得1分,未命中者得
分;两人都命中或都未命中,两人均得0分,设甲每次踢球命中的概率为
,乙每次踢球命中的概率为
,且各次踢球互不影响.
(1)经过1轮踢球,记甲的得分为
,求
的数学期望;
(2)若经过
轮踢球,用
表示经过第
轮踢球累计得分后乙得分高于甲得分的概率.
①求
,
,
;
②规定
,且有
,请根据①中
,
,
的值求出A、
,并求出数列
的通项公式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acbc6a613224461ade69362d46550474.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf31876698721a199c7c53c6b320aa86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
(1)经过1轮踢球,记甲的得分为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
(2)若经过
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99ba4e6b48109ec9e10138da17e82aec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb5c607987b73502db63f77c9799f4bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8790e22ceceab5921b32cb8602cdb71.png)
①求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8be646cd52d7f2f1714e7542e75810f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adad9633b73dfbbb3d84b4f15979e99e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87b21b872313f7d8c5b606981f954a1e.png)
②规定
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20dad8f0179ff7293905f1c89ab7d813.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06646651ac4ec8b20e091f839a19a405.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8be646cd52d7f2f1714e7542e75810f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adad9633b73dfbbb3d84b4f15979e99e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87b21b872313f7d8c5b606981f954a1e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/960b682f983b053dc9064cf29c97e250.png)
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4 . 已知数列
的首项为2,前
项和为
,
.若数列
的前
项和为
,则满足
成立的
的最小值为________ .
![](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/1855142817494316c4532c13a675f695.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6fc4b7329ae1322f7ba93fc9fe1a279.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)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c85f7fe924133eb2f62632f630d0c775.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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解题方法
5 . 从集合
中任意选出三个不同的数,若这三个数依次成等比数列,则这个等比数列公比为2的概率是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b066a50a7d6c91e10822b2ba69c9ed84.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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解题方法
6 . 已知事件
,
,
满足
,
,则下列结论正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8d493dbdf4efe16ac774db2a02cf3af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd061e199e9d763a2b5857e6f8ada09c.png)
A.如果![]() ![]() |
B.如果![]() ![]() ![]() |
C.如果![]() ![]() ![]() |
D.如果![]() ![]() ![]() |
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7 . 下列结论正确的是( )
A.标准差越大,则反映样本数据的离散程度越小. |
B.在回归直线方程![]() ![]() ![]() |
C.在回归分析模型中,残差平方和越小,说明模型的拟合程度越好. |
D.对分类变量![]() ![]() ![]() ![]() ![]() ![]() |
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8 . 如图(1),在
中,
,
,点
为
的中点.将
沿
折起到
的位置,使
,如图(2).
.
(2)在线段
上是否存在点
,使得
?若存在,求二面角
的正弦值;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77254996f9c0b31d0cf5a4f01ac46041.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/177678001b2ccde1db8f57fa5e017002.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bffd657e48b15b9b54a55817e2c26b22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a916d31a199e250556fb7478d9f57f7.png)
(2)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9072b0fae4133badde0a221234cca8f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3507a1f894fac6b554a49b1167965bbb.png)
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解题方法
9 . 下列命题中,正确的有( )
A.若随机变量![]() ![]() ![]() |
B.数据1,2,3,4,5,6,7,8,9,10的第![]() ![]() |
C.若随机变量![]() ![]() |
D.若![]() ![]() ![]() ![]() ![]() |
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10 . 已知数列
的前n项的积为
,
,则使得
成立的n的最大值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31f621bcf0de95972ec3e571baf10bb4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc25d179aca6dc451fc4e5da700b7280.png)
A.2021 | B.2022 | C.2023 | D.2024 |
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