解题方法
1 . 已知数列
是等比数列.
(1)若
,
,求
;
(2)若
,
,
,求
;
(3)若
,
,
,求n.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ea8d0e50065114b05ef2dc1ea1129cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/535fd9605b90ac7f0fed6025be9f851f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7eed39c7d611309b01476c15ab242308.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dc352f71e67467a7a9d59bb1e0633db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48d2ce4d32a8474ab55156f4c22617a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411641715d7f5132c34f1d6eace8cd8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7eed39c7d611309b01476c15ab242308.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdf53108bee755f5aa9a34ea4d163e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/535fd9605b90ac7f0fed6025be9f851f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d1e55ac6bf5e191105c01c72357a9b7.png)
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2 . 某工厂去年12月试产1050个高新电子产品,产品合格率为90%.从今年1月开始,工厂在接下来的两年中将生产这款产品.1月按去年12月的产量和产品合格率生产,以后每月的产量都在前一个月的基础上提高5%,产品合格率比前一个月增加0.4%,那么生产该产品一年后,月不合格品的数量能否控制在100个以内?
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3 . 已知数列
的首项
.
(1)若
为等差数列,公差
,证明数列
为等比数列;
(2)若
为等比数列,公比
,证明数列
为等差数列.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b13a6e1d671215fc96e4bee3541d1096.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5c1344592c925b273f2cb9b9e47ebbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5fdac31ceae0c61534e226e9c4e7e30.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91b9def0399f023143d66a9c45657b37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b79f232288a6d4b336e06153d81c41fe.png)
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4 . 用10000元购买某个理财产品一年.
(1)若以月利率0.400%的复利计息,12个月能获得多少利息(精确到1元)?
(2)若以季度复利计息,存4个季度,则当每季度利率为多少时,按季结算的利息不少于按月结算的利息(精确到
)?
(1)若以月利率0.400%的复利计息,12个月能获得多少利息(精确到1元)?
(2)若以季度复利计息,存4个季度,则当每季度利率为多少时,按季结算的利息不少于按月结算的利息(精确到
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/872626957f1321dd484c0209f75bbe7d.png)
您最近一年使用:0次
5 . 若等比数列
的第4项和第6项分别为48和12,求
的第5项.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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6 . 已知一个等差数列
前10项的和是310,前20项的和是1220.由这些条件能确定这个等差数列的首项和公差吗?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
您最近一年使用:0次
解题方法
7 . 已知数列
是等差数列.
(1)若
,
,求
;
(2)若
,
,求
;
(3)若
,
,
,求n.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06dd3c3b45125d4b484e2894992610f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/455153a2e91379d95841db772c70db3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a34a901aa78366ac960f5f4e7f1fcbac.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad6d8a8a57db1c2fc7f465d2cfd2aa78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f3cf6f2bbe20a404fea41a4d2b1c4c7.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ea8d0e50065114b05ef2dc1ea1129cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09ee990503e5b3608267fbd91cf16d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8000007201d28a54901c28b9feb6f62d.png)
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8 . 已知数列
是等差数列,p,q,s,
,且
.求证
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d717b62cf19a284dacacfb596fc1d9dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f1cefacc0165c52fe4e977c521c053.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25bfdb1a27a61169fa2f6d275c968d6e.png)
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9 . 在4与
之间插入3个数,使这5个数成等比数列,求插入的3个数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56d266a04f3dc7483eddbc26c5e487db.png)
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10 . 如果数列
中,
在
时恒成立,求证:
是等比数列.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22c21dca42ba104cd103c7c793fde337.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bcfc48f9bc23cc43085bdb910e7a136.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
您最近一年使用:0次