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# 等差数列培优

1. 1?2?3?4?.........?100 2. 1?3?5?7?9?.....?2011?2013

3. 2?4?6?8.........?98?100 4. 3?6?9?12.....?96?99

5. 2?5?8?11.......?302 6. 7?9?11?13.....?99?101

8. 1?5?9?13?.........?393 9. 5?10?15?20?.........?105

10. 1231998 ???....1999199919991999

11.

12.

13. 20?(0.30?0.31?0.32?...?0.68?0.69)的整数部分为 1121231234124849?(?)?(??)?(???)?...?(??...??) 2334445555505050501131351397?(?)?(??)?...?(??...?) 244666989898

1.

3. 5?5?5?....?5?5 4.

2391011111123910 2. 2?2?2?....?2?2 ?????24816326411111???....?()2012?()2013 392733

1. ?24?(?

3. 211?(?455)?365?455?211?545?545?365

4. (13.672?125?136.72?12.25?1367.2?1.875)?17.09

5. (17

6. (7

323??) 2. 3.71?27?3.71?23?3.71?60 234773721738?27?11)?(13?8?5) 27173917273913171337?3?2?1)?(15?7?4?3) 24782478

7. (1

555111?3?9)?(1?3?9) 993311993311

8. (285

9.

10.

11.

61012111?181?153)?(??) 71113711131?2?3?2?4?6?7?14?24 1?3?5?2?6?10?7?21?351?2?3?2?4?6?4?8?12?7?14?24 1?3?5?2?6?10?4?12?20?7?21?353?2?0.5?9?4?10?1.6?21?6?15 7?10?25?1.2?8?14?30?7?22?55

13?23?33?...?143?153

12. 3 33332?4?6?...?28?30

13.已知：a??1999?1999?19992000?2000?20002001?2001?2001，b??，c?? 1998?1998?19981999?1999?19992000?2000?2000 则abc?

14. 2007?20062006?2008?20072007?2006?20072007?2007?20082008

15. 2003?20052005?2005?20032002

16. 2006?

17. 3

20002005200520052006?2005?2007?2004 ?22006200620062006?2007?2005?5?31999?6?31998

1.

3.

1.

3.

1111111 2. ????(?) n?(n?1)nn?1n?(n?d)dnn?d?11?11d11???? 4. ??n?(n?1)?(n?2)2?n?(n?1)(n?1)?(n?2)?n?(n?d)nn?d?11111111 2. ???...????...?1?22?33?41999?20005?99?1313?17101?105111111111111 4. 1?2?3??????4?5?6?7 315357012016861220304256

5. 1?

6.

·

111 ??...?1?21?2?31?2?3?...?15111 ??...?11?13?1513?15?1729?31?33

1. (1?)?(1?)?(1?)?....?(1?

2. (1?

3. (1?)?(1?)?(1?)?....?(1?

12131411)?(1?) 2011201211111)?(1?)?(1?)?...?(1?)?(1?) 100410051006200520061214161111)?(1?)?(1?)?...?(1?) 10359

4. 1?2?3?4?..... 5. (7?9?11?...?101)?(5?7?9?...?99) ?2001?2002

6. 1?2?3?4?5?6?7?8?9?10?11?...?2007?2008?2009?2010

7. 9?99?999?9999?99999 8. (?179111315????)?23?21 31220304256