解题方法
1 . 如图所示的茎叶图记录了甲、乙两组各四名同学单位时间内引体向上的次数,乙组记录中有一个数据模糊,无法确认,在图中以
表示.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/3/b5f689f6-faad-4e6d-8fbc-e29ef90fa7af.png?resizew=151)
(1)如果
,求乙组同学单位时间内引体向上次数的平均数;
(2)如果
,分别从甲、乙两组中随机选取一名同学,求这两名同学单位时间内引体向上次数和为17的概率.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/3/b5f689f6-faad-4e6d-8fbc-e29ef90fa7af.png?resizew=151)
(1)如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e55956535f16521c8405760d003bf67.png)
(2)如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c8677bd74a14c5dfeb1ddd298dddf39.png)
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2 . 化简
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/783de213823c8796415f382571bc8042.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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3 . 现对某类文物进行某种物性指标检测,从1000件中随机抽取了200件,测得了它的物性指标值,得到如下频率分布直方图,据此估计这1000件文物中物性指标值不小于95的件数为( )
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/8a34aafb-b90a-4f06-ba07-e95a0a18ca35.png?resizew=386)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/15/8a34aafb-b90a-4f06-ba07-e95a0a18ca35.png?resizew=386)
A.34 | B.67 | C.340 | D.670 |
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2021-07-12更新
|
772次组卷
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3卷引用:青海省2021年12月普通高中学业水平考试数学试题
名校
4 . 已知数列
是等差数列,且
.
(1)求数列
的通项公式;
(2)若等比数列
满足
,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28c44515c4c5d2c7a34d0ea3e982c73d.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2295a16d913129bd3a60ffcf7f4fc92e.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/08eb71ecf8d733b6932f4680874dbbf3.png)
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2020-12-28更新
|
469次组卷
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3卷引用:青海省2021年12月普通高中学业水平考试数学试题
名校
5 . 已知集合
{
,
},则
的真子集个数为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73f4b04c45b214ed061fe2a43f5b51ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c95b6be4554f03bf496092f1acdfbb89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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2020-12-14更新
|
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4卷引用:青海省2021年12月普通高中学业水平考试数学试题
解题方法
6 . 如图,在三棱锥
中,侧棱
底面
,
,
、
分别是棱
、
的中点.
![](https://img.xkw.com/dksih/QBM/2020/11/3/2585234825994240/2585584311795712/STEM/e82264977d5540d8b1b28ce973780d55.png?resizew=182)
(Ⅰ)证明:
平面
;
(Ⅱ)证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/2020/11/3/2585234825994240/2585584311795712/STEM/e82264977d5540d8b1b28ce973780d55.png?resizew=182)
(Ⅰ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f9d682e5d3cc8573574d8d11636758.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(Ⅱ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc90fee532e50d319081d571410421.png)
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2020-11-04更新
|
308次组卷
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2卷引用:青海省2021年12月普通高中学业水平考试数学试题
7 . 等比数列
中,若
是方程
的两根,则
的值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb1ef611373c17c7e42ed5cc2074cd72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ec2efe3408c8d1ee8158ed01f6e997b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8db9fb61e388bd71f3671fb07e00e3aa.png)
A.6 | B.![]() | C.![]() | D.1 |
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2018-08-09更新
|
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3卷引用:青海省2021年12月普通高中学业水平考试数学试题