设
是公比不为1的等比数列,
为
,
的等差中项.
(1)求
的公比;
(2)若
,
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/390636a89883bd64bf8da9bf8654aff9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75d4841023ab41c5159beea9a4b3efd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
更新时间:2022-06-29 14:30:55
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【推荐1】在
中,角A,B,C的对边为a,b,c,已知
,
,
是等差数列.
(1)若a,b,c是等比数列,求
;
(2)若
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e7167cd55af72b5699802b277c33326.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30f7eaffde85b29b76ac40b5981ada36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17497a284ddace3ee09fc81c2302628f.png)
(1)若a,b,c是等比数列,求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03005d17bf564371ad29fea41f5c650.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffe7a93172d308a58200e3c722fe1072.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d6c3e00a78921faf110ffb26d93bb2c.png)
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【推荐2】
的内角
的对边分别为
,角
成等差数列,
.
(1)若
,求
和
;
(2)若
的面积为
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e258ab9e600435b37465092243d99f6.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4580cc037c0c760c728cdbb74a8154c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
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解题方法
【推荐1】已知
为等差数列,公差为d,
是公比为2的等比数列,且
,
.
(1)证明:
;
(2)求集合
的子集个数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/769fe52ac96348d3b12d23d06d702595.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d4660b8e4504f8ad6fe504690c8d033.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d38c4c234dd55eaf29979489df6f99b.png)
(2)求集合
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7b4a71393ca550f45ffc21354ab9cf0.png)
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【推荐2】在“①
,
;②
,
”两个条件中任选一个,补充到下面问题中,并解答.
已知正项等比数列
的前
项和为
,满足___________.
(1)求数列
的通项公式;
(2)求数列
的前
项和
.
注:如果选择两个条件分别解答,按第一个解答计分.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbddd4c506ce0cb04dfb117415c682f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0863cf59114f905e9ad3debc5572792.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25fc6e4698a74a39097e891812c976ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6df1038200f2d97a52c716aab6c3bcb6.png)
已知正项等比数列
![](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)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b191044f5c024f377d999910b78b422.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
注:如果选择两个条件分别解答,按第一个解答计分.
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【推荐1】设等比数列
满足a1+a3=10,a2+a4=5.求:a1a2…an的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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【推荐2】在等比数列{an}中,公比
,其前n项和为Sn,且S2=6,___________.
(1)求数列{an}的通项公式;
(2)设
,且数列{cn}满足c1=1,cn+1﹣cn=bn+1bn,求数列{cn}的通项公式.
从①.S4=30,②.S6﹣S4=96,③.a3是S3与2的等差中项,这三个条件中任选一个,补充到上面问题中的横线上,并作答.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f71acdb04454c77e1e25ad4f336cccfe.png)
(1)求数列{an}的通项公式;
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff6253244b3e96a9cc1203e6f6a8913c.png)
从①.S4=30,②.S6﹣S4=96,③.a3是S3与2的等差中项,这三个条件中任选一个,补充到上面问题中的横线上,并作答.
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【推荐1】王同学入读某大学金融专业,过完年刚好得到红包6000元,她计划以此作为启动资金进行理投资,每月月底获得的投资收益是该月月初投入资金的20%,并从中拿出1000元作为自己的生活费,余款作为资金全部投入下个月,如此继续.设第n个月月底的投资市值为an.
(1)求证:数列{
-5000}为等比数列;
(2)如果王同学想在第二年过年的时候给奶奶买一台全身按摩椅(商场标价为12899元),将一年后投资市值全部取出来是否足够?
(1)求证:数列{
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(2)如果王同学想在第二年过年的时候给奶奶买一台全身按摩椅(商场标价为12899元),将一年后投资市值全部取出来是否足够?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/86e4f54dca2ac2b70f1bbc16e54a4938.png)
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【推荐2】各项都为整数的数列
满足
,
,前6项依次成等差数列,从第5项起依次成等比数列.
(1)求数列
的通项公式;
(2)求出所有的正整数m,使得
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3299d1d394efc1381671b1632e6e87e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/674b8ec980dee2fcc9f6d2682cb8e358.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)求出所有的正整数m,使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/088d98f71f331d45f7543a5dc881df6b.png)
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