1 . 等比数列的前
项和
已知
为等比数列且公比为
,
为其前
项和.
(1)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61b7a07ade5913a6e6b54dbf1c23a5f3.png)
________ 或者![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d0980e3f744e203ae45c4bbb442e336.png)
________
(2)我们用方法________ 推导
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61b7a07ade5913a6e6b54dbf1c23a5f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d0980e3f744e203ae45c4bbb442e336.png)
(2)我们用方法
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
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2 . 等比数列的性质
已知
为等比数列,公比为
,
为其前
项和.
(1)若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8647b84bfbc7d827f56be74888b9fdb6.png)
______ ;
(2)当
时,
,________ ,
为等比数列;
(3)若等比数列
共
项,记
为诸奇数项和,
为诸偶数项和,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/186fad5c3b123434e46e02c26dcc3c32.png)
____ ;
已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c618d7069d2e18c8164ed0e6fa7811f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8647b84bfbc7d827f56be74888b9fdb6.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1d236a265a6cc0f3d06a0e568ffa907.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7ce01c8a13621ad26ea353b067dfaa8.png)
(3)若等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5631bc01b998a4b3fabd9e131699dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9df956d8d43778655131703be9ad9a41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16ce99d82b6ad34142c6920031a454e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/186fad5c3b123434e46e02c26dcc3c32.png)
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23-24高二上·江苏·课后作业
3 . 等比数列的通项公式
若
为等比数列,公比为
.
(1)
的通项公式为_______ ,
(2)
为递增数列的充要条件为_____ ;
为递减数列的充要条件为_____ ;
为常数列的充要条件为______ .
若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)
![](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/83cf38189d5cbf627d2b82ac0eb76006.png)
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23-24高二上·江苏·课后作业
4 . 等比数列的性质
若
为等比数列,公比为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
(1)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5e44ac9118b8f9b6177f178a655fb3a.png)
_______
(2)若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25f3247e615880b3cda21ade9d0eea0f.png)
_______ ,
(3)若_______ ,则
为等比数列.
若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5e44ac9118b8f9b6177f178a655fb3a.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fb679318d0c9819b82e51a1750b502a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25f3247e615880b3cda21ade9d0eea0f.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e40ebba1ff31c193ff699fd53a5cd3d0.png)
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23-24高二上·江苏·课后作业
5 . 等比数列的定义
(1)一般地,如果一个数列从第二项起,每一项与它的前一项所得的比都等于___ ,那么这个数列就叫作等比数列,这个常数叫作等比数列的公比,通常用
表示.
(2)如果数列
满足
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32ff3f9ee4c62803165f629bd03497e3.png)
_______ ,则
为等比数列.
(1)一般地,如果一个数列从第二项起,每一项与它的前一项所得的比都等于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
(2)如果数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffa01f03fb074bff35b35e07047d11b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32ff3f9ee4c62803165f629bd03497e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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23-24高二上·江苏·课后作业
6 . 等比中项
(1)如果三个数
成等比数列,则
叫作
的____ .
(2)如果
为
的等比中项,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5f1e5d29de6e4d72bfed62d9c14dde5.png)
_______ .
(1)如果三个数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e96d444cb9c5db8ff0829ef8a30c3d20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
(2)如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5f1e5d29de6e4d72bfed62d9c14dde5.png)
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7 . 将体积为1的四面体第一次挖去以各棱中点为顶点的构成的多面体,第二次再将剩余的每个四面体均挖去以各棱中点为顶点的构成的多面体,如此下去,共进行了
次.则第一次挖去的几何体的体积是__________ ;这
次共挖去的所有几何体的体积和是__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/223ed9652852ca4d996fd1f20808df9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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名校
解题方法
8 . 英国著名物理学家牛顿用“作切线”的方法求函数零点时,给出的“牛顿数列”在航空航天中应用广泛,若数列
满足
,则称数列
为牛顿数列
如果函数
,数列
为牛顿数列,设
,且
,
则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac326f9f4ad78d0053c113f823ea6d60.png)
___________
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e976c0663fa749ca749f99842d21ca03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33610d2a46105e3c8456257221d3d07b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e976c0663fa749ca749f99842d21ca03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c90282d4a37c9a20620d4bbb0c263cae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27af938f6500dad80a84f808ec8012cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e976c0663fa749ca749f99842d21ca03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3441f05da2cc524bfbb88d0fbfe61158.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed8a372611ee460d12713bbd018813f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac326f9f4ad78d0053c113f823ea6d60.png)
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名校
解题方法
9 . 设
,其中
,
,
,
成公差为d的等差数列,
,
,
成公比为3的等比数列,则d的最小值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bb8932303f10c4414a9bac540cd23bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f65fc200f10b97588a0c9896277c9c64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fd71bc7e6668f90f259ad0b06dd60c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5da4cd81500bdb43118150dbdb1541e6.png)
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2022-11-25更新
|
771次组卷
|
9卷引用:4.3 等比数列(4)
(已下线)4.3 等比数列(4)河南省安阳市2022-2023学年高三上学期期中数学文科试题河南省2023届高三上学期期中考试理科数学试题河南省2023届高三上学期期中考试文科数学试题河南省十所名校2022-2023学年高三上学期期中考试理科数学试题河南省安阳市2022-2023学年高三上学期期中数学理科试题福建省永春第一中学2022-2023学年高二上学期12月月考数学试题湖北省襄阳市第五中学2022-2023学年高三上学期12月月考数学试题(已下线)拓展三:数列与不等式 -【帮课堂】2022-2023学年高二数学同步精品讲义(人教A版2019选择性必修第二册)
解题方法
10 . 设
是首项为
的等比数列,
是其前
项和,若
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/614306cc3f34bdee4d5d885b79667645.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6eb0ed014b7f84b8f138fbed3d9e27f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/614306cc3f34bdee4d5d885b79667645.png)
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