Search found 751 matches
- Tue Jan 29, 2013 11:58 am
- Forum: Social Lounge
- Topic: May We Post Regional Problems?
- Replies: 2
- Views: 5381
Re: May We Post Regional Problems?
Yep! Go ahead and post problems. Good luck at the BdMO.
- Sun Dec 23, 2012 11:20 pm
- Forum: News / Announcements
- Topic: Posting BDMO 2013 problems: ZERO tolerance!
- Replies: 7
- Views: 14328
Re: Posting BDMO 2013 problems: ZERO tolerance!
So another new year at BdMO forum and time to impose embargo. Please don't post divisional MO problems. Don't risk your life!
- Wed Aug 15, 2012 9:51 pm
- Forum: Introductions
- Topic: আমি জয়
- Replies: 1
- Views: 4815
Re: আমি জয়
ফোরামে স্বাগতম। আশা করি নিয়মিত আলোচনায় যুক্ত থাকবে।
- Mon Jul 16, 2012 1:44 pm
- Forum: News / Announcements
- Topic: IMO-2012 result of Bangladesh team
- Replies: 4
- Views: 6996
Re: IMO-2012 result of Bangladesh team
Congratulations! I am planning to change the banner of the forum for a while to honor our heroes!
- Thu Jul 12, 2012 1:19 am
- Forum: International Mathematical Olympiad (IMO)
- Topic: IMO 2012: Day 2 Problem 6
- Replies: 1
- Views: 5549
IMO 2012: Day 2 Problem 6
Find all positive integers $n$ for which there exist non-negative integers $a_1,a_2,\cdots, a_n$ such that \[\frac{1}{2^{a_1}}+\frac{1}{2^{a_2}}+\cdots+\frac{1}{2^{a_n}}=\frac{1}{3^{a_1}}+\frac{2}{3^{a_2}}+\cdots+\frac{n}{3^{a_n}}=1\]
- Thu Jul 12, 2012 1:02 am
- Forum: International Mathematical Olympiad (IMO)
- Topic: IMO 2012: Day 2 Problem 5
- Replies: 5
- Views: 8303
IMO 2012: Day 2 Problem 5
Let $ABC$ be a triangle with $\angle {ACB}=90^0$ and let $D$ be the foot of the altitude from $C$. Let $X$ be a point in the interior of the segment $CD$. Let $K$ be the point on the segment $AX$ such that $BK=BC$. Similarly, let $L$ be the point on the segment $BX$ such that $AL=AC$. Let $M$ be the...
- Wed Jul 11, 2012 11:29 pm
- Forum: International Mathematical Olympiad (IMO)
- Topic: IMO 2012: Day 2 Problem 4
- Replies: 4
- Views: 8042
IMO 2012: Day 2 Problem 4
Find all functions $f:\mathbb{Z}\rightarrow \mathbb{Z}$, such that for all $a+b+c=0$ holds:
\[f(a)^2+f(b)^2+f(c)^2=2f(a)f(b)+2f(b)f(c)+2f(c)f(a).\]
\[f(a)^2+f(b)^2+f(c)^2=2f(a)f(b)+2f(b)f(c)+2f(c)f(a).\]
- Tue Jul 10, 2012 11:56 pm
- Forum: International Mathematical Olympiad (IMO)
- Topic: IMO 2012: Day 1 Problem 2
- Replies: 12
- Views: 16378
Re: IMO 2012: Day 1 Problem 2
It seems that there is no $a_1$ thanks for pointing out.
- Tue Jul 10, 2012 11:51 pm
- Forum: International Mathematical Olympiad (IMO)
- Topic: IMO 2012: Day 1 Problem 3
- Replies: 1
- Views: 6096
IMO 2012: Day 1 Problem 3
The liar's guessing game is a game played between two players $A$ and $B$. The rules of the game depend on two positive integers $k$ and $n$ which are known to both players. At the start of the game $A$ chooses integers $x$ and $N$ with $1 \le x \le N.$ Player $A$ keeps $x$ secret, and truthfully te...
- Tue Jul 10, 2012 11:31 pm
- Forum: International Mathematical Olympiad (IMO)
- Topic: IMO 2012: Day 1 Problem 2
- Replies: 12
- Views: 16378
IMO 2012: Day 1 Problem 2
Let $n \ge 3$ be an integer, and let $a_2, a_3, \ldots , a_n$ be positive real numbers such that $a_2\cdots a_n = 1.$
Prove that \[(1+a_2)^2(1+a_3)^3\cdots (1+a_n)^n > n^n\]
Prove that \[(1+a_2)^2(1+a_3)^3\cdots (1+a_n)^n > n^n\]