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Tech support and questions about AoPS classes and materials
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k a July Highlights and 2025 AoPS Online Class Information
jwelsh   0
Jul 1, 2025
We are halfway through summer, so be sure to carve out some time to keep your skills sharp and explore challenging topics at AoPS Online and our AoPS Academies (including the Virtual Campus)!

[list][*]Over 60 summer classes are starting at the Virtual Campus on July 7th - check out the math and language arts options for middle through high school levels.
[*]At AoPS Online, we have accelerated sections where you can complete a course in half the time by meeting twice/week instead of once/week, starting on July 8th:
[list][*]MATHCOUNTS/AMC 8 Basics
[*]MATHCOUNTS/AMC 8 Advanced
[*]AMC Problem Series[/list]
[*]Plus, AoPS Online has a special seminar July 14 - 17 that is outside the standard fare: Paradoxes and Infinity
[*]We are expanding our in-person AoPS Academy locations - are you looking for a strong community of problem solvers, exemplary instruction, and math and language arts options? Look to see if we have a location near you and enroll in summer camps or academic year classes today! New locations include campuses in California, Georgia, New York, Illinois, and Oregon and more coming soon![/list]

MOP (Math Olympiad Summer Program) just ended and the IMO (International Mathematical Olympiad) is right around the corner! This year’s IMO will be held in Australia, July 10th - 20th. Congratulations to all the MOP students for reaching this incredible level and best of luck to all selected to represent their countries at this year’s IMO! Did you know that, in the last 10 years, 59 USA International Math Olympiad team members have medaled and have taken over 360 AoPS Online courses. Take advantage of our Worldwide Online Olympiad Training (WOOT) courses
and train with the best! Please note that early bird pricing ends August 19th!
Are you tired of the heat and thinking about Fall? You can plan your Fall schedule now with classes at either AoPS Online, AoPS Academy Virtual Campus, or one of our AoPS Academies around the US.

Our full course list for upcoming classes is below:
All classes start 7:30pm ET/4:30pm PT unless otherwise noted.

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0 replies
jwelsh
Jul 1, 2025
0 replies
k i Adding contests to the Contest Collections
dcouchman   1
N Apr 5, 2023 by v_Enhance
Want to help AoPS remain a valuable Olympiad resource? Help us add contests to AoPS's Contest Collections.

Find instructions and a list of contests to add here: https://artofproblemsolving.com/community/c40244h1064480_contests_to_add
1 reply
dcouchman
Sep 9, 2019
v_Enhance
Apr 5, 2023
k i Zero tolerance
ZetaX   49
N May 4, 2019 by NoDealsHere
Source: Use your common sense! (enough is enough)
Some users don't want to learn, some other simply ignore advises.
But please follow the following guideline:


To make it short: ALWAYS USE YOUR COMMON SENSE IF POSTING!
If you don't have common sense, don't post.


More specifically:

For new threads:


a) Good, meaningful title:
The title has to say what the problem is about in best way possible.
If that title occured already, it's definitely bad. And contest names aren't good either.
That's in fact a requirement for being able to search old problems.

Examples:
Bad titles:
- "Hard"/"Medium"/"Easy" (if you find it so cool how hard/easy it is, tell it in the post and use a title that tells us the problem)
- "Number Theory" (hey guy, guess why this forum's named that way¿ and is it the only such problem on earth¿)
- "Fibonacci" (there are millions of Fibonacci problems out there, all posted and named the same...)
- "Chinese TST 2003" (does this say anything about the problem¿)
Good titles:
- "On divisors of a³+2b³+4c³-6abc"
- "Number of solutions to x²+y²=6z²"
- "Fibonacci numbers are never squares"


b) Use search function:
Before posting a "new" problem spend at least two, better five, minutes to look if this problem was posted before. If it was, don't repost it. If you have anything important to say on topic, post it in one of the older threads.
If the thread is locked cause of this, use search function.

Update (by Amir Hossein). The best way to search for two keywords in AoPS is to input
[code]+"first keyword" +"second keyword"[/code]
so that any post containing both strings "first word" and "second form".


c) Good problem statement:
Some recent really bad post was:
[quote]$lim_{n\to 1}^{+\infty}\frac{1}{n}-lnn$[/quote]
It contains no question and no answer.
If you do this, too, you are on the best way to get your thread deleted. Write everything clearly, define where your variables come from (and define the "natural" numbers if used). Additionally read your post at least twice before submitting. After you sent it, read it again and use the Edit-Button if necessary to correct errors.


For answers to already existing threads:


d) Of any interest and with content:
Don't post things that are more trivial than completely obvious. For example, if the question is to solve $x^{3}+y^{3}=z^{3}$, do not answer with "$x=y=z=0$ is a solution" only. Either you post any kind of proof or at least something unexpected (like "$x=1337, y=481, z=42$ is the smallest solution). Someone that does not see that $x=y=z=0$ is a solution of the above without your post is completely wrong here, this is an IMO-level forum.
Similar, posting "I have solved this problem" but not posting anything else is not welcome; it even looks that you just want to show off what a genius you are.

e) Well written and checked answers:
Like c) for new threads, check your solutions at least twice for mistakes. And after sending, read it again and use the Edit-Button if necessary to correct errors.



To repeat it: ALWAYS USE YOUR COMMON SENSE IF POSTING!


Everything definitely out of range of common sense will be locked or deleted (exept for new users having less than about 42 posts, they are newbies and need/get some time to learn).

The above rules will be applied from next monday (5. march of 2007).
Feel free to discuss on this here.
49 replies
ZetaX
Feb 27, 2007
NoDealsHere
May 4, 2019
One old Long List No.1
prof.   1
N an hour ago by prof.
Source: Netherland proposal
A circle is inscribed in a rhombus. In each corner of the rhombus, a circle is inscribed such that it touches two sides of the rhombus and inscribed circle. These corner circles have radii $r_1$ and $r_2$ and the radius of the inscribed circle is $r$. If $r_1$ and $r_2$ are natural numbers and $r=r_1\cdot r_2$, find the value of $r_1,r_2$ and $r$.
1 reply
prof.
May 29, 2025
prof.
an hour ago
AOPS MO Introduce
MathMaxGreat   79
N an hour ago by AleMM
$AOPS MO$

Problems: post it as a private message to me or @jerryZYang, please post it in $LATEX$ and have answers

6 Problems for two rounds, easier than $IMO$

If you want to do the problems or be interested, reply ’+1’
Want to post a problem reply’+2’ and message me
Want to be in the problem selection committee, reply’+3’
79 replies
MathMaxGreat
Yesterday at 1:04 AM
AleMM
an hour ago
Cannot post Latex, Account is already 23 days old
lrnnz   2
N an hour ago by bpan2021
Hello, a class i'm in requires us to post problems in the High School Math section, but the posts I make are hard to read as they don't contain any Latex. I was told my account needs to at least be 2 weeks old before I can start making posts with Latex, but i still can't
2 replies
lrnnz
an hour ago
bpan2021
an hour ago
My Unsolved Problem
ZeltaQN2008   2
N an hour ago by AleMM
Let $x_1, x_2, \ldots, x_n$ be positive integers such that $\gcd(x_1, x_2, \ldots, x_n) = 1$. Define
\[
S_k = x_1^k + x_2^k + \cdots + x_n^k
\]for all $k \in \mathbb{Z}^+$. Prove that
\[
\gcd(S_1, S_2, \ldots, S_n) \mid \mathrm{lcm}(1, 2, \ldots, n).
\]
2 replies
ZeltaQN2008
2 hours ago
AleMM
an hour ago
incenter and midpoints of arcs of <B,<C collinear iff AC + BC = 3AB
parmenides51   3
N 2 hours ago by Captainscrubz
Source: 2014 Sharygin Geometry Olympiad Final Round 9.6
Let $I$ be the incenter of triangle $ABC$, and $M, N$ be the midpoints of arcs $ABC$ and $BAC$ of its circumcircle. Prove that points $M, I, N$ are collinear if and only if$ AC + BC = 3AB$.

(A. Polyansky)
3 replies
parmenides51
Aug 3, 2018
Captainscrubz
2 hours ago
Product of corners of rectangles not divisible by p
gghx   2
N 2 hours ago by Tkn
Source: SMO open 2024 Q5
Let $p$ be a prime number. Determine the largest possible $n$ such that the following holds: it is possible to fill an $n\times n$ table with integers $a_{ik}$ in the $i$th row and $k$th column, for $1\le i,k\le n$, such that for any quadruple $i,j,k,l$ with $1\le i<j\le n$ and $1\le k<l\le n$, the number $a_{ik}a_{jl}-a_{il}a_{jk}$ is not divisible by $p$.

Proposed by oneplusone
2 replies
gghx
Aug 3, 2024
Tkn
2 hours ago
A geometry problem
Lttgeometry   0
2 hours ago
The incircle \((I)\) of triangle \(ABC\) touches \(BC,\ CA,\ AB\) at points \(D, E, F\), respectively. Let \(J\) be the intersection point of \(DI\) and \(EF\). Points \(M\) and \(N\) lie on \(IE\) and \(IF\), respectively, such that \(JM \parallel DF\) and \(JN \parallel DE\). Let $G$ is the intersection of $MN$ and $BC$. Prove that $IG \perp AJ$.
0 replies
Lttgeometry
2 hours ago
0 replies
A snail will make it to the top
Snark_Graphique   0
2 hours ago
Source: Myanmar IMO Training
Let $n \geq 2$ be an integer and $h > 0$ be a real number. Feeling discouraged while taking the mock IMO, Ma Pu Kywae looks outside the window and observes $n$ snails labelled $1, 2, \dotsc, n$ climbing up a fence of height $h$ units. Initially, all the snails start from the ground, and each snail $k$ steadily climbs up at the speed of $2^k$ units per minute until it reaches the top. At the end of each minute, one of the snails whose height is strictly less than $h$ drops onto the ground, resetting its journey up the wall.

Find the largest possible value of the height $h$ so that no matter how the snails drop, at least one will eventually make it to the top.
0 replies
Snark_Graphique
2 hours ago
0 replies
Prefix sums of divisors are perfect squares
CyclicISLscelesTrapezoid   41
N 2 hours ago by eg4334
Source: ISL 2021 N3
Find all positive integers $n$ with the following property: the $k$ positive divisors of $n$ have a permutation $(d_1,d_2,\ldots,d_k)$ such that for $i=1,2,\ldots,k$, the number $d_1+d_2+\cdots+d_i$ is a perfect square.
41 replies
CyclicISLscelesTrapezoid
Jul 12, 2022
eg4334
2 hours ago
Italian WinterCamps test07 Problem5
mattilgale   58
N 3 hours ago by lpieleanu
Source: ISL 2006, A1, AIMO 2007, TST 1, P1
A sequence of real numbers $ a_{0},\ a_{1},\ a_{2},\dots$ is defined by the formula
\[ a_{i + 1} = \left\lfloor a_{i}\right\rfloor\cdot \left\langle a_{i}\right\rangle\qquad\text{for}\quad i\geq 0;
\]here $a_0$ is an arbitrary real number, $\lfloor a_i\rfloor$ denotes the greatest integer not exceeding $a_i$, and $\left\langle a_i\right\rangle=a_i-\lfloor a_i\rfloor$. Prove that $a_i=a_{i+2}$ for $i$ sufficiently large.

Proposed by Harmel Nestra, Estionia
58 replies
mattilgale
Jan 29, 2007
lpieleanu
3 hours ago
functional equation with two variables
Sayan   6
N 3 hours ago by ParthivCalculus
Source: ISI(BS) 2005 #3
Let $f$ be a function defined on $\{(i,j): i,j \in \mathbb{N}\}$ satisfying

(i) $f(i,i+1)=\frac{1}{3}$ for all $i$

(ii) $f(i,j)=f(i,k)+f(k,j)-2f(i,k)f(k,j)$ for all $k$ such that $i <k<j$.

Find the value of $f(1,100)$.
6 replies
Sayan
May 20, 2012
ParthivCalculus
3 hours ago
AOPS website lag
henryli3333   8
N Today at 2:21 AM by henryli3333
I dont know if this is just me but the AOPS website seems to be lagging a lot, sometimes it takes 30 seconds to a minute for a page to load, my friend is having the same issue, does anyone know what's going on?
8 replies
henryli3333
Jul 11, 2025
henryli3333
Today at 2:21 AM
Aopswiki is broken
NNNfailure1434   7
N Today at 1:15 AM by twang2015
if you go to aopswiki, and search up something like Chinese remainder theorem, then it says something like media wiki internal error
7 replies
NNNfailure1434
Yesterday at 6:28 PM
twang2015
Today at 1:15 AM
k advertisment
garfield0515   6
N Jul 9, 2025 by garfield0515
I got a pm saying that one of my previous posts about advertising was removed and I just learned that it was not allowed, and there may be further reports and it would be great if you could excuse those since I just learned that.
please send me a pm or something
garfield0515
6 replies
garfield0515
Jul 8, 2025
garfield0515
Jul 9, 2025
k Forum question
Kawhi2   3
N May 29, 2024 by KangarooPrecise
How does Aops rank user created forums? Like, do they rank it by posts, or threads?
3 replies
Kawhi2
May 29, 2024
KangarooPrecise
May 29, 2024
Forum question
G H J
G H BBookmark kLocked kLocked NReply
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Kawhi2
966 posts
#1
Y by
How does Aops rank user created forums? Like, do they rank it by posts, or threads?
Z Y
The post below has been deleted. Click to close.
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bpan2021
2712 posts
#2
Y by
They are ranked by the amount of active threads in the forum.
Z Y
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MrMustache
3155 posts
#3
Y by
what constitutes an active thread?
Z Y
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KangarooPrecise
1563 posts
#4
Y by
bpan2021 wrote:
They are ranked by the amount of active threads in the forum.

So spam things are useless
Z Y
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