已知数列{an}是公差不为零的等差数列,a1=2,且a2,a4,a8成等比数列.
(1)求数列{an}的通项公式;
(2)求数列{an·
}的前n项和.
(1)求数列{an}的通项公式;
(2)求数列{an·
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6498b4f0637a8f2888a6469e74a5d83e.png)
更新时间:2021-03-23 16:43:29
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解答题-问答题
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适中
(0.65)
解题方法
【推荐1】将
个正数排成
行
列:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a4225fd32ea75fcd14a768d4b5b523e.png)
其中每一行的数成等差数列,每一列的数成等比数列,并且各列的公比都相等,若
,
,
.
(1)求
;
(2)设
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43d0231cc6e97157cdc1cff0f94fb1d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a4225fd32ea75fcd14a768d4b5b523e.png)
其中每一行的数成等差数列,每一列的数成等比数列,并且各列的公比都相等,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b51541c6afa99ce5e9014e1526c56c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c4549355f20cea9035d70f8ce4294bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eddaa8e92853bff0fbda9b7eaded43a.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ed1412fc99b8d3bf7190af663d23344.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09985cdcc0b75023ca08d0a24e37b586.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
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解答题-证明题
|
适中
(0.65)
解题方法
【推荐2】设
是等差数列,
是等比数列,且
.
(1)求
与
的通项公式;
(2)设
的前
项和为
,求证:
;
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f6eba282321f5d17e3de9b6544e9f6f.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.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/e75d9867b074723183a89460d62af4de.png)
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解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】已知
是公差不为0的等差数列,
,且
,
的等比中项为
.
(1)求通项公式
;
(2)若
,求数列
的前2022项和T.
![](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/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
(1)求通项公式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/216876de04325fd250c38c485cbc34b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.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】已知正项数列
是公差为2的等差数列,且24是
与
的等比中项.
(1)求数列
的通项公式;
(2)若
,求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b53c7c703af0668331b4d6d5470e544.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3783e69ef5a6a0af566ff4e21ccf03.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a2fce97beff11a17a1334dbb51f53be2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fce83115a50f99e08e9a2db7267aeed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
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【推荐1】已知数列
满足,
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cac9dc3dd3b74ede00849cb406c0de5.png)
.
(1)设
,求数列
前三项的值及数列
的通项公式;
(2)设
,求
的前n项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a75739be7640de2ab1c3e191b9857a40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cac9dc3dd3b74ede00849cb406c0de5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/132e9579e58d8d5225e2340e1f43adf1.png)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58bed7b8134a626d08644cd871bbecd6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/326be0620b9aeb2caeb634aed6646c39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57ef6d44448092ebdb9e4a49d866a749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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【推荐2】已知数列
前
项和
,且
.
(1)求数列
的通项公式;
(2)若数列
满足
,求数列
前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.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/08e7d0c282cd14c00ec4e3ff544b2b45.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
(2)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38ef4c4439b36c2847b0056a116d56d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f069c27042a3b6705ceab1f11443f87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38ef4c4439b36c2847b0056a116d56d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
您最近一年使用:0次