1 . 如图是瑞典科学家科赫在1904年构造的能够描述雪花形状的图案.图案的作法是:从一个正三角形开始,把每条边分成三等份,然后以各边的中间一段为底边分别向外作正三角形,再去掉底边,这样的过程称为一次操作.反复进行这种操作过程,就得到一条“雪花”状的曲线,并记
次操作后的曲线为
,周长为
.设原正三角形
的边长为1,
即对应图1,则进行二次操作后,曲线
(对应图3)的顶点数为___________ ;若进行
次操作后,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c8a8515a27b443ef421a03e8ad032b6.png)
___________ .
![](https://img.xkw.com/dksih/QBM/2021/7/10/2761137675239424/2793147703115776/STEM/e244a5ff-b835-4ad2-829a-3e9e42268511.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9275bd8ce17fcc4a786510b008414ab0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c8a8515a27b443ef421a03e8ad032b6.png)
![](https://img.xkw.com/dksih/QBM/2021/7/10/2761137675239424/2793147703115776/STEM/e244a5ff-b835-4ad2-829a-3e9e42268511.png)
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2021-08-24更新
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4卷引用:湖北省武汉市江岸区2020-2021学年高二上学期期末数学试题
解题方法
2 . 已知等差数列
的公差为2,且
成等比数列,
是数列
的前
项和,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/1302b567c6f72c5909158c0521351032.png)
![](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/dc4e70b360f988fdbd92300ab22c4613.png)
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2卷引用:湖北省宜昌市、荆州市、荆门市等市2020-2021学年高二下学期期末联考数学试题
3 . 某高中食堂鲜奶站提供
、
两种鲜奶,他们经过统计分析发现:第一次购买的人购买
种鲜奶的概率为
、购买
种鲜奶的概率为
,而前一次购买
种鲜奶的人下一次来购买
种鲜奶的概率为
、购买
种鲜奶的概率为
,前一次购买
种鲜奶的人下一次来购买
种鲜奶的概率为
、购买
种鲜奶的概率也是
,如此往复.记某人第
次来购买
种鲜奶的概率为
.则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c3eaee0866bc35ffa5a39a989d2dfa7.png)
___________ ﹔经过一段时间的经营每天来购买鲜奶的人稳定在800人,假定这800人都已购买过很多次该两种鲜奶,那么公司每天应至少准备
种鲜奶___________ 份.
![](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/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf31876698721a199c7c53c6b320aa86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dac452fbb5ef6dd653e7fbbef639484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d266a04f3dc7483eddbc26c5e487db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b2a698891d42c70b597f0da4f215f09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf83e20035c3afd6d26ebfd53d768a70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c3eaee0866bc35ffa5a39a989d2dfa7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
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3卷引用:湖北省华中师范大学第一附属中学2020-2021学年高二上学期期末数学试题
湖北省华中师范大学第一附属中学2020-2021学年高二上学期期末数学试题天津市十二区县重点学校2022届高三下学期一模考前模拟数学试题(已下线)专题20 概率与统计常考小题归类(15大题型)(练习)
名校
4 . 把正整数排列成如图甲的三角形数阵,然后擦去第偶数行中的奇数和第奇数行中的偶数,得到如图乙的三角形数阵,再把图乙中的数按从小到大的顺序排成一列,得到数列
,则
(1)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96088842e9f4107229ea88fd978cb8cd.png)
_________________ ;(2)若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
__________________
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96088842e9f4107229ea88fd978cb8cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b8243c5965a844b36d5fc5988b83362.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f3cb8d72bb2e281b943b3b430138ef7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/7/42bb4810-1dd5-48bf-9beb-8ed13ce9c2f2.png?resizew=443)
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名校
解题方法
5 . 已知数列
满足
,
且
,则该数列的前9项之和为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2693734765399876e9e93cdb110231c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06012919e81aa74440b5b1d4eb3d15f4.png)
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2020-09-07更新
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6卷引用:湖北省黄石市第二中学2020-2021学年高二上学期期末数学试题
湖北省黄石市第二中学2020-2021学年高二上学期期末数学试题江西省景德镇市2019-2020学年高三第三次质检数学(文)试题江西省景德镇市2019-2020学年高三第三次质检试卷数学(理)试题安徽省庐巢六校2019-2020学年高一下学期6月联考数学试题(已下线)考点20 等差数列与等比数列-2021年新高考数学一轮复习考点扫描(已下线)专题11 数列前n项和的求法 微点1 公式法求和