Search found 181 matches

by ahmedittihad
Tue Feb 06, 2018 1:14 pm
Forum: News / Announcements
Topic: geometry(iranian geometry olympiad 2017)
Replies: 4
Views: 4195

Re: geometry(iranian geometry olympiad 2017)

Okay so you're having difficulty in understanding what clockwise is. In the picture $ABC$ is clockwise and $A_1B_1C_1$ is counterclockwise.
by ahmedittihad
Sun Feb 04, 2018 2:54 am
Forum: News / Announcements
Topic: geometry(iranian geometry olympiad 2017)
Replies: 4
Views: 4195

Re: geometry(iranian geometry olympiad 2017)

What help do you need?
by ahmedittihad
Sun Feb 04, 2018 2:47 am
Forum: National Math Olympiad (BdMO)
Topic: BDMO 2017 National round Secondary 1
Replies: 19
Views: 7792

Re: BDMO 2017 National round Secondary 1

Both the solutions are completely wrong. Because the 20 cases aren't equally likely.
by ahmedittihad
Wed Jan 24, 2018 10:09 pm
Forum: National Math Olympiad (BdMO)
Topic: BDMO 2017 National round Secondary 4
Replies: 5
Views: 2365

Re: BDMO 2017 National round Secondary 4

ahmedittihad wrote:
Fri Feb 10, 2017 9:05 pm
$OM = 6.5$
This is a typing mistake, it should be $CM=6.5$.
by ahmedittihad
Thu Dec 14, 2017 12:46 pm
Forum: Higher Secondary Level
Topic: A strange NUMBER THEORY Problem
Replies: 4
Views: 4854

Re: A strange NUMBER THEORY Problem

Bigganchinta is wrong.
by ahmedittihad
Fri Dec 01, 2017 7:30 pm
Forum: Combinatorics
Topic: Combi Marathon
Replies: 48
Views: 26489

Re: Combi Marathon

Problem 20

A pentagon with all sides equal is given. Prove that the circles having those sides as diameters can't cover the the entire region of that pentagon.
by ahmedittihad
Mon Nov 27, 2017 4:41 pm
Forum: Secondary Level
Topic: Sylhet - 2014
Replies: 2
Views: 1652

Re: Sylhet - 2014

You're actually misinterpreting the question. The problem basically gives us that $(x+1) + (x+2) + ... + (x+y) =976 $. With $x+1$ being the first missing page and $x+y$ the last missing page. So we need to find $y$. $(x+1) + (x+2) + ... + (x+y) = xy + \dfrac {y(y+1)}{2}=976$ So, $y(x+ \dfrac {y+1}{2...
by ahmedittihad
Sun Nov 26, 2017 7:28 pm
Forum: Geometry
Topic: Geometry Marathon : Season 3
Replies: 115
Views: 58319

Re: Geometry Marathon : Season 3

Problem $49$ Let $ABC$ be an acute-angled triangle with $AB\not= AC$. Let $\Gamma$ be the circumcircle, $H$ the orthocentre and $O$ the centre of $\Gamma$. $M$ is the midpoint of $BC$. The line $AM$ meets $\Gamma$ again at $N$ and the circle with diameter $AM$ crosses $\Gamma$ again at $P$. Prove th...
by ahmedittihad
Sun Oct 01, 2017 10:25 pm
Forum: International Mathematical Olympiad (IMO)
Topic: IMO $2017$ P$1$
Replies: 4
Views: 6734

Re: IMO $2017$ P$1$

Case 1: $a_0\equiv 0\pmod{3}$. We have $a_m\equiv 0\pmod{3}\,\,\forall m\geq 0$. If $a_0=3$ then $a_{3m}=3\,\,\forall m\geq 0$, therefore $a_0=3$ satisfying the condition of the problem. If $a_0=3k$ for some $k>1$. We will prove that there is an index $m_0$ such that $a_{m_0}<a_0$, and therefore (b...
by ahmedittihad
Fri Sep 01, 2017 2:15 pm
Forum: Geometry
Topic: Geometry Marathon : Season 3
Replies: 115
Views: 58319

Re: Geometry Marathon : Season 3

Problem $44$ Let $\triangle ABC$ be an acute angled triangle satisfying the conditions $AB > BC$ and $AC > BC$. Denote by $O$ and $H$ the circumcentre and orthocentre, respectively, of $\triangle ABC$. Suppose that the circumcircle of the triangle $AHC$ intersects the line $AB$ at $M$ different from ...