1 . 在数列
中,已知
,设
为
的前n项和.
(1) 求证:数列
是等差数列;
(2) 求
;
(3) 是否存在正整数
,使
成等差数列?若存在,求出
的值;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb0054c34ec26e44ceef7d708f081a1c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
(1) 求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b09ba0d55a8817f39a34fd920b6ec30.png)
(2) 求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(3) 是否存在正整数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55336fb58f8e6ea100d0f62390a7265a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69324e3871131573e5cd62b3e4105f19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14c5fe8a9ad42e52a8a40242865c6752.png)
您最近一年使用:0次
2020-01-18更新
|
502次组卷
|
3卷引用:2017届江苏徐州等四市高三11月模拟考试数学卷
名校
解题方法
2 . 在①
,②
,③
三个条件中任选一个,补充在下面问题中,并加以解答.
已知
的内角A,B,C所对的边分别是a,b,c,若_____,且a,b,c成等差数列,则
是否为等边三角形?若是,写出证明;若不是,说明理由.
注:如果选择多个条件分别解答,按第一个解答计分.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76e0d4945f6b06a3f0791ab7ee3d276d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4542e5dfa3702fb2824682f0731a1c9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f1d5b50db0b87df7a8907a4e0699b6.png)
已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
注:如果选择多个条件分别解答,按第一个解答计分.
您最近一年使用:0次
2020-04-05更新
|
3080次组卷
|
15卷引用:2020届山东省济宁市高三下学期第五次线上考试数学试题
2020届山东省济宁市高三下学期第五次线上考试数学试题2020届山东省青岛市第一中学高三下学期第五次在线考试数学试题江苏省镇江市第一中学2020-2021学年高三上学期12月阶段性考试数学试题广东省梅州市2021届高三下学期3月总复习质检数学试题2020届山东省高三下学期开学收心检测数学试题海南省2019-2020学年高三高考调研测试数学试题(已下线)第5篇——三角函数与解三角形-新高考山东专题汇编江苏省南京市秦淮中学2020-2021学年高三上学期期初调研数学试题海南、山东等新高考地区2021届高三上学期期中备考金卷数学(B卷)试题2021届高三高考必杀技之结构开放题专练广东省梅州市2021届高三一模数学试题河北省衡水市第十四中学2020-2021学年高二下学期一调(月考)数学试题(已下线)专题18 三角恒等变换-学会解题之高三数学万能解题模板【2022版】(已下线)NO.2 方法专区——解答题的解题技法(一)(讲)-2022年高考数学二轮复习讲练测(新教材·新高考地区专用)江苏省镇江市2019-2020学年高二下学期期末数学试题
3 . 已知正项数列
的前n项和为
,若数列
是公差为
的等差数列,且
是
的等差中项.
(1)证明数列
是等比数列,并求数列
的通项公式;
(2)若
是数列
的前n项和,若
恒成立,求实数
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bed16925686f967168e4057a543ece2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acbc6a613224461ade69362d46550474.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58b3175ab6772cd611f9c42771a9467d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14877bf6d7297f02feff3468abf01f69.png)
(1)证明数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41cf1da18d91f7c98086553d157d1a87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b7a1a4869a0329cdf22169ce8df5ba7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
您最近一年使用:0次
2020-03-20更新
|
484次组卷
|
7卷引用:2020届安徽省六安市第一中学高三下学期模拟卷(六)数学(理)试题
2020届安徽省六安市第一中学高三下学期模拟卷(六)数学(理)试题2020届安徽省六安市第一中学高三下学期模拟卷(六)数学(文)试题(已下线)强化卷06(3月)-冲刺2020高考数学之少丢分题目强化卷(山东专版)(已下线)第25讲 等比数列及其前n项和-2021年新高考数学一轮专题复习(新高考专版)银川一中17校联考2021届高三数学(文)试题银川一中、昆明一中强强联合2021届高三5月高考猜题卷数学(文)试题宁夏回族自治区银川市第一中学2021届高考猜题卷数学(文)试题
名校
解题方法
4 . 已知数列
的前
项的和为
,记
.
(1)若
是首项为
,公差为
的等差数列,其中
,
均为正数.
①当
,
,
成等差数列时,求
的值;
②求证:存在唯一的正整数
,使得
.
(2)设数列
是公比为
的等比数列,若存在
,
(
,
,
)使得
,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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d9b4196cb1b032566b318290d7194b0.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
①当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9632e7e5a6eb0c85cb44940c60618d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7e82778985cd2e9f80ca7b7cabb1a85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57483e04fd1840c87ac5325157149877.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4336e21aa2b3fdf15f1b72463714830e.png)
②求证:存在唯一的正整数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cef9a7f77ebabd7f7f26c2aea18b683f.png)
(2)设数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/442ed72e1c8c3586b799220e9fadaed3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11bc05f41215f9894e11d1df0465751a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11bc05f41215f9894e11d1df0465751a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68efb961550a83f5a52a4fd16917d27c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14c23407e3cdc55f7e4df2c8cf335396.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f5c6b818605e0ea64c59e9edde27614.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
您最近一年使用:0次
2020-03-20更新
|
323次组卷
|
4卷引用:2020届江苏省南通中学高三上学期第二次调研测试数学试题
2020届江苏省南通中学高三上学期第二次调研测试数学试题2016届江苏省南京市高三第三次模拟考试数学试卷(已下线)《2018届优等生百日闯关系列》【江苏版】专题二 第五关 以子数列或生成数列为背景的解答题2020届江苏省南通市如皋中学、如东中学高三下学期阶段联合调研数学试题
名校
解题方法
5 . 记
为等比数列
的前n项和,已知
,
.
(1)求
的通项公式
(2)求
;
(3)判断
,
,
是否成等差数列,若是,写出证明过程;若不是,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a0bf1ebce75e828fd999cc04a319502.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1dfe5b322577f02fd19caab8cf20170.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(3)判断
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebadf2b3ec3dc92cd902eff76085ad46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a35d79a1b4df9e4aade6a92f35bea2.png)
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2020-03-04更新
|
288次组卷
|
2卷引用:2020届湖南省衡阳市第八中学高三上学期第六次月考数学(文)试题
6 . 在
中,角
,
,
所对的边分别是
,
,
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3834548edd9f93869dba95db642af8cd.png)
.
(1)证明:
为
,
的等差中项;
(2)若
,
,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3834548edd9f93869dba95db642af8cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4318b591a11bd4e463d21bc5b7ff9904.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/541b16fdc230c1bf727de73ba0aea2a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ab1c19b66cda3fb899f06d9a25e973c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
您最近一年使用:0次
2020-01-06更新
|
802次组卷
|
7卷引用:四川省资阳市2019-2020学年高三上学期第二次诊断考试数学(文)试题
名校
解题方法
7 . 设
的三边长分别为
若![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff63feffcfb5457be58e33643e8c37bc.png)
(1)比较
与
的大小;
(2)求数列
的通项公式;
(3)作
于
记
与
的面积之差的绝对值为
则在数列
中,是否存在某两项
使
依次成等差数列?证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed9b981aebc8c09de65e4bf84b8f0f22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4c7d4a9ccf5d954e7469f10829e0cd2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff63feffcfb5457be58e33643e8c37bc.png)
(1)比较
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f46fae204190f132c1d8eb7535cfe87c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fa1a233995948a7b3cdd75c66444dac.png)
(2)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f329b217e1051b23f0d61023cdc6e69.png)
(3)作
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f9a240582f9a17ff1274a71bdffcedc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/17796fbd290adaaecda64e960ecd1309.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c857b8cc422b0550ffc7c30a253a3b78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7949c2adcabf91e95cb381220903ab96.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b807aa7f208cd051f843b29cc3c1c334.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a8a4d244655d284fc0cf9f092aaf2e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0864165f2452eb6ca8715d70e696143f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecd1c78c7abef0ee88a148049ef89888.png)
您最近一年使用:0次
2019-11-06更新
|
962次组卷
|
3卷引用:上海市金山中学2018-2019学年高三下学期3月月考数学试题
8 . 对于给定的正整数
,若数列
满足
对任意正整数
恒成立,则称数列
是
数列,若正数项数列
,满足:
对任意正整数
恒成立,则称
是
数列;
(1)已知正数项数列
是
数列,且前五项分别为
、
、
、
、
,求
的值;
(2)若
为常数,且
是
数列,求
的最小值;
(3)对于下列两种情形,只要选作一种,满分分别是 ①
分,②
分,若选择了多于一种情形,则按照序号较小的解答记分.
① 证明:数列
是等差数列的充要条件为“
既是
数列,又是
数列”;
②证明:正数项数列
是等比数列的充要条件为“数列
既是
数列,又是
数列”.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0981b9ded724ecec5735ced14d684bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3205ae03910cf77c8cf5b1ac7372d839.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e94a2fd143f31e7981007589aed7ff7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06da966dc473fe3addf33e4d25f530e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3205ae03910cf77c8cf5b1ac7372d839.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2db6addea8060eea6953e2faa6c3d5e9.png)
(1)已知正数项数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac8065f6ed7bf3568ec9df743e70a285.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14f14adcde2c42c774c827fb3ecef852.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b287cf4370beceda3d58fb85f5f7b8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/074c228ffc7b1e306f8410afe7bc4b5c.png)
(3)对于下列两种情形,只要选作一种,满分分别是 ①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b06e95b57b7a81cd81d05557a11fa92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd3304e23f3b0f9569c4140ca89b6498.png)
① 证明:数列
![](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/4b287cf4370beceda3d58fb85f5f7b8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66a945987b037c1d04cbb2c875ab5569.png)
②证明:正数项数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d766cbb87f501f8a0447af6104400590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd6c507b32cdaeb48f3e863b4250a9d6.png)
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9 . 设Sn为数列{an}的前n项和,已知a1 =1,a3=7,an=2an-1+a2 - 2(n≥2).
(I)证明:{an+1)为等比数列;
(2)求{an}的通项公式,并判断n,an,S是否成等差数列?
(I)证明:{an+1)为等比数列;
(2)求{an}的通项公式,并判断n,an,S是否成等差数列?
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2018-10-23更新
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471次组卷
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11卷引用:湖北省武汉市部分市级示范高中2019届高三十月联考理科数学试题
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名校
解题方法
10 . 已知
是各项都为正数的数列,其前
项和为
,且
为
与
的等差中项.
(1)求证:数列
为等差数列;
(2)设
,求
的前
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/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b7e761be88728b3db50c2abd4377c12.png)
(1)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a30a2ed20d8c6bc465574bbf812b6b9d.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b20224f6ba644d885435646a9b91b45.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/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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