Tag Archives: 박승균

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: 2011-18 Continuous Function and Differentiable Function

Let f(x) be a continuous function on I=[a,b], and let g(x) be a differentiable function on I. Let g(a)=0 and c≠0 a constant. Prove that if

|g(xf(x)+c g′(x)|≤|g(x)| for all x∈I,

then g(x)=0 for all x∈I.

The best solution was submitted by Seungkyun Park (박승균), 수리과학과 2008학번. Congratulations!

Here is his Solution of Problem 2011-18.

Alternative solutions were submitted by 김범수 (수리과학과 2010학번, +3), 장경석 (2011학번, +3),  김태호 (2011학번, +2), 김재훈 (EEWS대학원, +2).

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Solution: 2011-12 Determinant

Let M=(mi,j)1≤i,j≤n be an n×n matrix such that mi,j=i(i+1)(i+2)…(i+j-2). (Note that m1,1=1.) What is the determinant of M?

The best solution was submitted by Seungkyun Park (박승균), 수리과학과 2008학번. Congratulations!

Here is his Solution of Problem 2011-12.

Alternative solutions were submitted by 조상흠 (수리과학과 2010학번, +3), 장경석 (2011학번, +3), 김원중 (2011학번, +3), 박민재 (2011학번, +3),   서기원 (수리과학과 2009학번, +3), 김범수 (2010학번, +3), 어수강 (서울대학교, +3),  조위지 (Stanford Univ. 물리학과 박사과정, +3).

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Solution:2009-19 Two matrices

Let A and B be n×n matrices over the real field R. Prove that if A+B is invertible, then A(A+B)-1B=B(A+B)-1A.

The best solution was submitted by SeungKyun Park (박승균), 2008학번. Congratulations!

Here is his Solution of Problem 2009-19.

Alternative solutions were submitted by 옥성민 (수리과학과 2003학번, +3), 노호성 (물리학과 2008학번, +3), 송지용 (수리과학과 2006학번, +3), 김현 (2008학번, +3), 정성구 (수리과학과 2007학번, +3), 이재송 (전산학과 2005학번, +3), 정지수 (수리과학과 2007학번, +3), 김호진 (2009학번, +3), 최석웅 (수리과학과 2006학번, +3), 김환문 (물리학과 2008학번, +3),  류종하 (서울대학교 전기과 2008학번). One incorrect solution was received. Thank you for the participation.

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