1/3单选题
难度：
1.已知数列{an}中，
=2，(n-1)
=n
(n
), 则
=
=2，(n-1)=n(n), 则= | A | n |
| B | 2n |
| C | 3n |
| D | 4n |
- 提示1：
- PGltZyB3aWR0aD0xNyBoZWlnaHQ9MjEgc3JjPSJodHRwczovL3AyLnFpbmdndW8uY29tL0cxL00wMC8xQS82NS9yQkFDRTFOWl8xZUNTVzNZQUFBQlVMeXFRMzgwNzgucG5nIj49Mm4=
正确答案：Qg==
6Kej77ya55SxPGltZyB3aWR0aD0xNzEgaGVpZ2h0PTQyIHNyYz0iaHR0cHM6Ly9wMS5xaW5nZ3VvLmNvbS9HMS9NMDAvMUEvNjUvckJBQ0UxTlpfMlBTbDFrTkFBQUVRR3dtTko0MzEzLnBuZyI+MjxpbWcgd2lkdGg9NzAgaGVpZ2h0PTIxIHNyYz0iaHR0cHM6Ly9wMS5xaW5nZ3VvLmNvbS9HMS9NMDAvREUvNTAvckJBQ0ZGTlpfMlB4c3RKZ0FBQUJyakw0SzFBMjk4LnBuZyI+KzxpbWcgd2lkdGg9MzIgaGVpZ2h0PTIxIHNyYz0iaHR0cHM6Ly9wMS5xaW5nZ3VvLmNvbS9HMS9NMDAvMUEvNjUvckJBQ0UxTlpfMkN4eHVQM0FBQUJlaHFkVzJFOTE2LnBuZyI+
2/3单选题
难度：
2.数列{an}中，=1,
(n
),则=
=1,(n),则= | A |  |
| B | n |
| C | . |
| D |  |
- 提示1：
- 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
正确答案：RA==
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
3/3单选题
难度：
3.在数列{an}中，=1,前n项和
满足n
-(n+3)
=0,则{an}的通项公式为（）
=1,前n项和满足n-(n+3)=0,则{an}的通项公式为（） | A |  |
| B | n |
| C |  |
| D | n(n+1) |
- 提示1：
- 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
正确答案：QQ==
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