Monthly Archives: December 2011

Concluding 2011 Fall

Thanks all for participating POW actively. Here’s the list of winners:

1st prize: Jang, Kyoungseok (장경석) – 2011학번

2nd prize: Suh, Gee Won (서기원) – 수리과학과 2009학번

3rd prize: Kim, Bumsu (김범수) – 수리과학과 2010학번

4th prize: Park, Seungkyun (박승균) – 수리과학과 2008학번

5th prize: Park, Minjae (박민재) – 2011학번

Congratulations! As announced earlier, we have nicer prize this semester – iPad 16GB for the 1st prize, iPod Touch 32GB for the 2nd prize, etc.

장경석 (2011학번) 28 pts
서기원 (2009학번) 27 pts
김범수 (2010학번) 22 pts
박승균 (2008학번) 14 pts
박민재 (2011학번) 13 pts
강동엽 (2009학번) 11 pts
김태호 (2011학번) 9 pts
김원중 (2011학번) 3 pts
곽영진 (2011학번) 3 pts
조상흠 (2010학번) 3 pts
라준현 (2008학번) 3 pts
배다슬 (2008학번) 3 pts
이재석 (2007학번) 3 pts
최민수 (2011학번) 3 pts
문상혁 (2010학번) 2 pts
박상현 (2010학번) 2 pts

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Solution: 2011-24 (n-k) choose k

Evaluate the sum \[ \sum_{k=0}^{[n/2]} (-4)^{n-k} \binom{n-k}{k} ,\] where [x] denotes the greatest integer less than or equal to x.

The best solution was submitted by Kang, Dongyub (강동엽), 전산학과 2009학번. Congratulations!

Here is his Solution of Problem 2011-24.

Alternative solutions were submitted by 장경석 (2011학번, +3), 서기원 (수리과학과 2009학번, +3), 김범수 (수리과학과 2010학번, +3), 박준하 (하나고등학교 2학년, +3).

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