已知等差数列{an}中,
,前5项和
.
(1)求
的通项公式.
(2)若
,求数列
前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1928c254cfada1f75a5cd1e34db5a63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f09af4ec36b53aeb644ed16cfe725957.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54cb8010c98d0dd088ccfaba994dc19d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2d51f9147b8265c0276c1f2c2659197.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbd85b79372dc6e596d465f738c3c300.png)
2019·陕西·高考模拟 查看更多[2]
更新时间:2019-04-16 00:18:04
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解答题-问答题
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适中
(0.65)
【推荐1】已知数列
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
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(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87fdf6138885afb33e97e8a2a1c0f2c5.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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【推荐2】已知数列
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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您最近一年使用:0次