解题方法
1 . 已知有穷数列
共有
项(整数
),首项
,设该数列的前
项和为
,且
,其中常数
.
(Ⅰ)求证:数列
为等比数列;
(Ⅱ)若
,数列
满足
,求
的和(用
表示).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5631bc01b998a4b3fabd9e131699dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbeaed9ec21e090defafcfeefe0059c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.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/921101da86f17e4f4b6d254ca51fde3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d33da711e50e96568facb18cef27165.png)
(Ⅰ)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57def6b0c89b6f806344696963162289.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a81a4d5c42a5fe3aa2fe43774bcafac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9da5be3f28f79bf2b371ef4592b998ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
您最近一年使用:0次
2 . 设数列{an}满足:a1=1,an+1=3an,n∈N*.设Sn为数列{bn}的前n项和,已知b1≠0,
2bn–b1=S1•Sn,n∈N*.
(Ⅰ)求数列{an},{bn}的通项公式;
(Ⅱ)设
,求数列{cn}的前n项和Tn;
(Ⅲ)证明:对任意n∈N*且n≥2,有
+
+…+
<
.
2bn–b1=S1•Sn,n∈N*.
(Ⅰ)求数列{an},{bn}的通项公式;
(Ⅱ)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba66ef1e765632f1f62a896a55345ec0.png)
(Ⅲ)证明:对任意n∈N*且n≥2,有
![](https://img.xkw.com/dksih/QBM/2016/4/6/1578863833063424/1578863833587712/STEM/5cbea60fcd9a41df820c1348be5fb289.png)
![](https://img.xkw.com/dksih/QBM/2016/4/6/1578863833063424/1578863833587712/STEM/cd58906f007c4bbb91a3c58d0302b741.png)
![](https://img.xkw.com/dksih/QBM/2016/4/6/1578863833063424/1578863833587712/STEM/7b9080738c67409fa6e3b7faba7dfb8d.png)
![](https://img.xkw.com/dksih/QBM/2016/4/6/1578863833063424/1578863833587712/STEM/acf6c460768a40beaf739da22cdbf90a.png)
您最近一年使用:0次
2016-12-03更新
|
1614次组卷
|
4卷引用:2015届天津市南开区高三一模理科数学试卷
3 . 已知数列{an}与{bn}满足bn+1an+bnan+1=(﹣2)n+1,bn=
,n∈N*,且a1=2.
(1)求a2,a3的值
(2)设cn=a2n+1﹣a2n﹣1,n∈N*,证明{cn}是等比数列
(3)设Sn为{an}的前n项和,证明
+
+…+
+
≤n﹣
(n∈N*)
![](https://img.xkw.com/dksih/QBM/2014/6/5/1571759012970496/1571759018713088/STEM/b8eb63c30ed740169eae93d38e4d96d5.png)
(1)求a2,a3的值
(2)设cn=a2n+1﹣a2n﹣1,n∈N*,证明{cn}是等比数列
(3)设Sn为{an}的前n项和,证明
![](https://img.xkw.com/dksih/QBM/2014/6/5/1571759012970496/1571759018713088/STEM/e13d541dd0f14d58a6a6f3108d16dca7.png)
![](https://img.xkw.com/dksih/QBM/2014/6/5/1571759012970496/1571759018713088/STEM/6ade77d0938046bbaaf003583813230f.png)
![](https://img.xkw.com/dksih/QBM/2014/6/5/1571759012970496/1571759018713088/STEM/03ad00b5caee4419bc1a91309f2b515b.png)
![](https://img.xkw.com/dksih/QBM/2014/6/5/1571759012970496/1571759018713088/STEM/49f9c22db34c43a48a1ff7291cce194a.png)
![](https://img.xkw.com/dksih/QBM/2014/6/5/1571759012970496/1571759018713088/STEM/e6eab64ac68d49c7973ccb42186ca003.png)
您最近一年使用:0次
真题
4 . 在数列
与
中,
,数列
的前
项和
满足
,
为
与
的等比中项,
.
(Ⅰ)求
的值;
(Ⅱ)求数列
与
的通项公式;
(Ⅲ)设
.证明
.
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/813be1cf542c45798e71fdc7ba882344.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/0b1f298ceb954a558ea1f4fad3f29af0.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/548ebffc86384a838d27814ae64fc871.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/813be1cf542c45798e71fdc7ba882344.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/a38d1b920aec483c96206d43eee90ac4.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/7a676c7243304dfdb9036b8769b2a157.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/1d0f16dc5a4f41d3adf5f484b898c9f2.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/be312a87633e46cf81335e2fc434e3db.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/b864f3e861b5427aa2be157dbb8a4e60.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/4348208411b44f8189ae0182150f73a9.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/c70e00a82c7a45f09ba87c7ab1646276.png)
(Ⅰ)求
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/e9b838c4e6534ea69e1262eb353cf9af.png)
(Ⅱ)求数列
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/813be1cf542c45798e71fdc7ba882344.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/0b1f298ceb954a558ea1f4fad3f29af0.png)
(Ⅲ)设
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/e32a4e148ded498aa8086a9b5eff70e9.png)
![](https://img.xkw.com/dksih/QBM/2010/4/1/1569688487706624/1569688630157312/STEM/fc145be6d0fe45cba96e4235a4dc4739.png)
您最近一年使用:0次