Search found 181 matches
- Fri Jan 13, 2017 6:37 pm
- Forum: National Math Olympiad (BdMO)
- Topic: BdMO National 2008: Secondary
- Replies: 5
- Views: 4018
Re: BdMO National 2008: Secondary
Is that a deriviative sign?
- Fri Jan 13, 2017 6:36 pm
- Forum: Site Support
- Topic: How to delete BdMO Forum Account?
- Replies: 2
- Views: 13334
Re: How to delete BdMO Forum Account?
erm, the forum was inactive, yes. But we can make it active. We're trying to do so.
- Fri Jan 13, 2017 6:31 pm
- Forum: Secondary Level
- Topic: Dhaka regional 16 P4
- Replies: 5
- Views: 5147
Re: Dhaka regional 16 P4
As $Z$ is defined as the reflected point of $X$ with right to $Y$, we get $ XY=YZ$. From there we get $XZ=2XY$.
- Fri Jan 13, 2017 4:43 pm
- Forum: Combinatorics
- Topic: USAMO 2008: Triangulation of a regular polygon
- Replies: 1
- Views: 2528
Re: USAMO 2008: Triangulation of a regular polygon
We'll show that $n = 2^x * (2^y +1)$. Where $(x,y)$ is an integer more than $-1$. Let us denote the triangle in the triariangulation which has the center of the circumcircle of the polygon * The Big Triangle*. By the condition, atleast 2 sides of the big triangle are the same. Let the vertices of th...
- Fri Jan 13, 2017 6:21 am
- Forum: Number Theory
- Topic: Pretty Diophantine Equation
- Replies: 2
- Views: 3094
Re: Pretty Diophantine Equation
The only solution is $(21,28)$.
- Fri Jan 13, 2017 6:18 am
- Forum: Secondary Level
- Topic: Books /Videos for taking Preparation
- Replies: 2
- Views: 3554
Re: Books /Videos for taking Preparation
As I said before, the important thing to do in Olympiads is to practise regularly. But seeing your shortage of time, you could just try to read the books I told you to.
- Thu Jan 12, 2017 9:48 pm
- Forum: Junior Level
- Topic: Coloring chessboard
- Replies: 1
- Views: 2341
Re: Coloring chessboard
The number of black cells $mod 2$ stays invarient. Whih is at the start an even number. So, the desired state is impossible to reach.
- Thu Jan 12, 2017 7:56 pm
- Forum: International Mathematical Olympiad (IMO)
- Topic: 2001 C7
- Replies: 1
- Views: 2545
2001 C7
A pile of $n$ pebbles is placed in a vertical column. This configuration is modified according to the following rules. A pebble can be moved if it is at the top of a column which contains at least two more pebbles than the column immediately to its right. (If there are no pebbles to the right, think...
- Thu Jan 12, 2017 12:48 am
- Forum: Combinatorics
- Topic: Combi Solution Writing Threadie
- Replies: 10
- Views: 13568
Re: Combi Solution Writing Threadie
Revive this?
- Wed Jan 11, 2017 8:29 pm
- Forum: Geometry
- Topic: IGO 2016 Advanced/1
- Replies: 2
- Views: 2955
Re: IGO 2016 Advanced/1
This formulation has many interesting extra problems.
$1.$ $B$ is the miquel point of quadrilateral $PEFQ$.
$2.$ $AB$ intersect circle $EFBX$ = $K$. Then, $K$ is the orthocenter of $\triangle PQX$
$3.$ $AB$ is a symmedian of both $\triangle ACD$ and $\triangle BEF$.
$1.$ $B$ is the miquel point of quadrilateral $PEFQ$.
$2.$ $AB$ intersect circle $EFBX$ = $K$. Then, $K$ is the orthocenter of $\triangle PQX$
$3.$ $AB$ is a symmedian of both $\triangle ACD$ and $\triangle BEF$.