试题：
(本小题满分  13分)设等差数列 满足 .（1）求 的通项公式；（2）求数列 的前n项和Sn及使得Sn最大的序号n的值． |
等比数列的定义及性质, 等差数列的定义及性质
2016-05-24
答案：
我来补答解：(1) 由  得 解得  ∴  ··························································································· 6分(2) 由 (1) 知，  ∴当n = 5时，Sn取得最大·········································································· 13分 |
略 |
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