1.

$abc=1$. Now apply AM-GM.

#2 directly follows from AM-GM. For #1, can you find a clever way to apply AM-GM?

- Wed Feb 14, 2018 4:59 am
- Forum: Algebra
- Topic: lowest Value
- Replies:
**2** - Views:
**42**

Hint:

1.
2.

1.

- Fri Jun 02, 2017 1:59 pm
- Forum: News / Announcements
- Topic: MPMS Problem Solving Marathon
- Replies:
**8** - Views:
**763**

PROBLEM 3:

Find all *odd* integers $n$ for which $4n^2-6n+45$ is a perfect square.

PROBLEM 4:

Find all positive integers $m$ and $n$ such that $7^m+11^n$ is a perfect square.

Find all *odd* integers $n$ for which $4n^2-6n+45$ is a perfect square.

PROBLEM 4:

Find all positive integers $m$ and $n$ such that $7^m+11^n$ is a perfect square.

- Wed May 24, 2017 12:15 am
- Forum: News / Announcements
- Topic: MPMS Problem Solving Marathon
- Replies:
**8** - Views:
**763**

This is a general problem solving marathon for members of Mymensingh Parallel Math School (MPMS). However, feel free to participate, even if you are not a member. PROBLEM 1: $p$ is a prime number of the form $4k+1$. Prove that there exists an integer $a$ so that $a^2+1$ is divisible by $p$. PROBLEM ...

- Sun Dec 04, 2016 9:33 pm
- Forum: Secondary Level
- Topic: Points contained in a bounded area
- Replies:
**1** - Views:
**349**

$n$ points lie on a plane so that the triangle formed by any three of them has an area of at most $1\;\text{unit}^2$. Prove that all the points are contained in a triangle with area of at most $4\;\text{unit}^2$.

- Mon Nov 07, 2016 10:19 pm
- Forum: Geometry
- Topic: Two triangles and three collinear points
- Replies:
**1** - Views:
**294**

We are given triangles $ABC$ and $DEF$ such that $D\in BC, E\in CA, F\in AB$, $AD\perp EF, BE\perp FD, CF\perp DE$. Let the circumcenter of $DEF$ be $O$, and let the circumcircle of $DEF$ intersect $BC,CA,AB$ again at $R,S,T$ respectively. Prove that the perpendiculars to $BC,CA,AB$ through $D,E,F$ ...

- Mon Nov 07, 2016 10:17 pm
- Forum: Combinatorics
- Topic: Bulldozer on the coordinate plane
- Replies:
**0** - Views:
**190**

On the coordinate plane, there are finitely many walls, (= disjoint line segments) none of which are parallel to either axis. A bulldozer starts at an arbitrary point and moves in the $+x$ direction. Every time it hits a wall, it turns at a right angle to its path, away from the wall, and continues ...

- Mon Nov 07, 2016 10:12 pm
- Forum: Number Theory
- Topic: Functional divisibility
- Replies:
**2** - Views:
**366**

$ k$ is a given natural number. Find all functions $ f: \mathbb{N}\rightarrow\mathbb{N}$ such that for each $ m,n\in\mathbb{N}$ the following holds: \[ f(m)+f(n)\mid (m+n)^k\]

- Mon Nov 07, 2016 10:10 pm
- Forum: Combinatorics
- Topic: Dominoes in a chessboard
- Replies:
**0** - Views:
**222**

A $100\times 100$ chessboard is cut into dominoes ($1\times 2$ rectangles). Two persons play the following game: At each turn, a player glues together two adjacent cells (which were formerly separated by a cut-edge). A player loses if, after his turn, the $100\times 100$ chessboard becomes connected...

- Mon Nov 07, 2016 12:32 pm
- Forum: Computer Science
- Topic: Programming Question
- Replies:
**6** - Views:
**2016**

To write a desktop app, you need to use a framework. I would recommend Qt, a very popular framework. Visit its website: https://www.qt.io/

- Mon Nov 07, 2016 11:59 am
- Forum: Combinatorics
- Topic: Largest convex polygon in an array
- Replies:
**0** - Views:
**203**

Draw a $2004\times 2004$ array of points. What is the largest integer $n$ for which it is possible to draw a convex $n$-gon whose vertices are chosen from the points in the array?