在公比为q的等比数列{an}中,已知a1=16,且a1,a2+2,a3成等差数列.
(Ⅰ)求q,an;
(Ⅱ)若q<1,求满足a1-a2+a3-…+(-1)2n-1a2n>10的最小的正整数n的值.
更新时间:2018-01-17 02:43:04
|
相似题推荐
解答题-问答题
|
适中
(0.65)
【推荐1】已知数列
是公差为
的等差数列,且
,
,
成等比数列.
(1)求数列
的通项公式;
(2)设
,求数列
的前
项和.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5da4cd81500bdb43118150dbdb1541e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc858b7a95c5006a44067022da09f667.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2616c944dabfb70137ff65d531b8a88f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d51f9147b8265c0276c1f2c2659197.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】已知数列
的前6项依次成等比数列,设公比为q(
),数列从第5项开始各项依次为等差数列,其中
,数列
的前n项和为
.
(1)求公比q及数列
的通项公式;
(2)若
,求项数n的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45482d31d1d7448c9f3922b4d2a55331.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eea1d535231a08df0e2d65316b0b7012.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(1)求公比q及数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af41f69faa99e847ee18d2de283542aa.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】如图是一个边长为1的正三角形,将每边三等分,以中间一段为边向形外作正三角形,并擦去中间一段,得图形(2),如此继续下去,得图形(3),…
(1)求第
个图形的边长
和周长
;
(2)求第
个图形的面积
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/19/9bb1f67a-9b84-4128-ab43-5a2c6097facf.png?resizew=480)
(1)求第
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcc31dcdb99754fc452ff2b92a2fb8c9.png)
(2)求第
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐2】已知数列
的前
项和为
,且
.
(1)求数列
的通项公式;
(2)若数列
的前
项和为
,证明:
.
![](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/48a57b5d8d6f1ed099ecad23ecb17aba.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0496f142d8ae5acb06e83526eaa3ef87.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/1a5468ad14fdfdc7c2ec17b42e174237.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】已知数列
中,
且数列
的前
项和
,又设
.
(Ⅰ)求证:数列
是等比数列;
(II)求数列
的通项
及前
项和
;
(III)求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/131b133a67fbb2c527ba166f0dede952.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5535f881ec1e1f95e47ec816bc28cb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03e632c1a772efc4d989db21db70b795.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c59748e8a89c186709ffea3f77705ed.png)
(Ⅰ)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d185b833d4c128fdb2916212516abe6b.png)
(II)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/686ece75006ad358f23314dc8a246e11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(III)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11c916b48252fa8b27432261040150cc.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐2】已知数列
的前
项和为
.
(1)求数列
的通项公式
;
(2)若
,
,求
;
(3)记
,若数列
中去掉数列
中的项后余下的项按原来的顺序组成数列
,求
的值.
![](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/5eb7cc43cfb7b80699bca2f523434d85.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9d803ea42100a942e02f29145ce98b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b519f2287a07079f6ca20588d06171f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4537fdbb4055cb3d0129526cc93cecd.png)
(3)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f62394979f2e6c479e60d7b350b2328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b783cf91e34e692ce8e171f0965cb53f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb4dff95b024b3161a52dfc594afe461.png)
您最近一年使用:0次