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Tech support and questions about AoPS classes and materials
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k a May Highlights and 2025 AoPS Online Class Information
jlacosta   0
May 1, 2025
May is an exciting month! National MATHCOUNTS is the second week of May in Washington D.C. and our Founder, Richard Rusczyk will be presenting a seminar, Preparing Strong Math Students for College and Careers, on May 11th.

Are you interested in working towards MATHCOUNTS and don’t know where to start? We have you covered! If you have taken Prealgebra, then you are ready for MATHCOUNTS/AMC 8 Basics. Already aiming for State or National MATHCOUNTS and harder AMC 8 problems? Then our MATHCOUNTS/AMC 8 Advanced course is for you.

Summer camps are starting next month at the Virtual Campus in math and language arts that are 2 - to 4 - weeks in duration. Spaces are still available - don’t miss your chance to have an enriching summer experience. There are middle and high school competition math camps as well as Math Beasts camps that review key topics coupled with fun explorations covering areas such as graph theory (Math Beasts Camp 6), cryptography (Math Beasts Camp 7-8), and topology (Math Beasts Camp 8-9)!

Be sure to mark your calendars for the following upcoming events:
[list][*]May 9th, 4:30pm PT/7:30pm ET, Casework 2: Overwhelming Evidence — A Text Adventure, a game where participants will work together to navigate the map, solve puzzles, and win! All are welcome.
[*]May 19th, 4:30pm PT/7:30pm ET, What's Next After Beast Academy?, designed for students finishing Beast Academy and ready for Prealgebra 1.
[*]May 20th, 4:00pm PT/7:00pm ET, Mathcamp 2025 Qualifying Quiz Part 1 Math Jam, Problems 1 to 4, join the Canada/USA Mathcamp staff for this exciting Math Jam, where they discuss solutions to Problems 1 to 4 of the 2025 Mathcamp Qualifying Quiz!
[*]May 21st, 4:00pm PT/7:00pm ET, Mathcamp 2025 Qualifying Quiz Part 2 Math Jam, Problems 5 and 6, Canada/USA Mathcamp staff will discuss solutions to Problems 5 and 6 of the 2025 Mathcamp Qualifying Quiz![/list]
Our full course list for upcoming classes is below:
All classes run 7:30pm-8:45pm ET/4:30pm - 5:45pm PT unless otherwise noted.

Introductory: Grades 5-10

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0 replies
jlacosta
May 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
Difficult combinatorics problem
shactal   0
an hour ago
Can someone help me with this problem? Let $n\in \mathbb N^*$. We call a distribution the act of distributing the integers from $1$
to $n^2$ represented by tokens to players $A_1$ to $A_n$ so that they all have the same number of tokens in their urns.
We say that $A_i$ beats $A_j$ when, when $A_i$ and $A_j$ each draw a token from their urn, $A_i$ has a strictly greater chance of drawing a larger number than $A_j$. We then denote $A_i>A_j$. A distribution is said to be chicken-fox-viper when $A_1>A_2>\ldots>A_n>A_1$ What is $R(n)$
, the number of chicken-fox-viper distributions?
0 replies
shactal
an hour ago
0 replies
Cubic and Quadratic
mathisreal   3
N an hour ago by macves
Source: CIIM 2020 P2
Find all triples of positive integers $(a,b,c)$ such that the following equations are both true:
I- $a^2+b^2=c^2$
II- $a^3+b^3+1=(c-1)^3$
3 replies
1 viewing
mathisreal
Oct 26, 2020
macves
an hour ago
Inspired by Zhejiang 2025
sqing   1
N an hour ago by WallyWalrus
Source: Own
Let $ x,y,z $ be reals such that $ 5x^2+6y^2+6z^2-8yz\leq 5. $ Prove that$$ x+y+z\leq \sqrt{6}$$
1 reply
sqing
4 hours ago
WallyWalrus
an hour ago
incircle excenter midpoints
danepale   9
N an hour ago by Want-to-study-in-NTU-MATH
Source: Middle European Mathematical Olympiad T-6
Let the incircle $k$ of the triangle $ABC$ touch its side $BC$ at $D$. Let the line $AD$ intersect $k$ at $L \neq D$ and denote the excentre of $ABC$ opposite to $A$ by $K$. Let $M$ and $N$ be the midpoints of $BC$ and $KM$ respectively.

Prove that the points $B, C, N,$ and $L$ are concyclic.
9 replies
danepale
Sep 21, 2014
Want-to-study-in-NTU-MATH
an hour ago
geometry
gggzul   0
2 hours ago
Let $ABC$ be a triangle with $\angle ACB=90^{\circ}$. $D$ is the midpoint of $AC$. Let the angle bisector of $\angle ACB$ cut $BD$ at $P$ and $G$ be the centroid of $ABC$. $(CPG)$ meets $BC$ at $Q\ne C$ and $R$ is the projection of $Q$ onto $AB$. Prove that $R, G, P, A$ lie on a common circle.
0 replies
gggzul
2 hours ago
0 replies
Maximum Area of Triangle ABC
steven_zhang123   0
2 hours ago
Let the coordinates of point \( A \) be \( (0,3) \). Points \( B \) and \( C \) are two moving points on the circle \( O \): \( x^2+y^2=25 \), satisfying \( \angle BAC=90^\circ \). Find the maximum area of \( \triangle ABC \).
0 replies
steven_zhang123
2 hours ago
0 replies
IMO 2016 Problem 4
termas   56
N 2 hours ago by sansgankrsngupta
Source: IMO 2016 (day 2)
A set of positive integers is called fragrant if it contains at least two elements and each of its elements has a prime factor in common with at least one of the other elements. Let $P(n)=n^2+n+1$. What is the least possible positive integer value of $b$ such that there exists a non-negative integer $a$ for which the set $$\{P(a+1),P(a+2),\ldots,P(a+b)\}$$is fragrant?
56 replies
termas
Jul 12, 2016
sansgankrsngupta
2 hours ago
Interesting inequalities
sqing   3
N 2 hours ago by sqing
Source: Own
Let $a,b,c \geq 0 $ and $ abc+2(ab+bc+ca) =32.$ Show that
$$ka+b+c\geq 8\sqrt k-2k$$Where $0<k\leq 4. $
$$ka+b+c\geq 8 $$Where $ k\geq 4. $
$$a+b+c\geq 6$$$$2a+b+c\geq 8\sqrt 2-4$$
3 replies
sqing
May 15, 2025
sqing
2 hours ago
Every popular person is the best friend of a popular person?
yunxiu   8
N 3 hours ago by HHGB
Source: 2012 European Girls’ Mathematical Olympiad P6
There are infinitely many people registered on the social network Mugbook. Some pairs of (different) users are registered as friends, but each person has only finitely many friends. Every user has at least one friend. (Friendship is symmetric; that is, if $A$ is a friend of $B$, then $B$ is a friend of $A$.)
Each person is required to designate one of their friends as their best friend. If $A$ designates $B$ as her best friend, then (unfortunately) it does not follow that $B$ necessarily designates $A$ as her best friend. Someone designated as a best friend is called a $1$-best friend. More generally, if $n> 1$ is a positive integer, then a user is an $n$-best friend provided that they have been designated the best friend of someone who is an $(n-1)$-best friend. Someone who is a $k$-best friend for every positive integer $k$ is called popular.
(a) Prove that every popular person is the best friend of a popular person.
(b) Show that if people can have infinitely many friends, then it is possible that a popular person is not the best friend of a popular person.

Romania (Dan Schwarz)
8 replies
yunxiu
Apr 13, 2012
HHGB
3 hours ago
2021 EGMO P2: f(xf(x)+y) = f(y) + x^2 for rational x, y
anser   80
N 3 hours ago by math-olympiad-clown
Source: 2021 EGMO P2
Find all functions $f:\mathbb{Q}\to\mathbb{Q}$ such that the equation
\[f(xf(x)+y) = f(y) + x^2\]holds for all rational numbers $x$ and $y$.

Here, $\mathbb{Q}$ denotes the set of rational numbers.
80 replies
anser
Apr 13, 2021
math-olympiad-clown
3 hours ago
alcumus going crazy?
LittleSnake____   15
N 5 hours ago by Craftybutterfly
all of a sudden, the alcumus forum has gotten completely exploded by gamebot's posts.

https://artofproblemsolving.com/community/c63h3570498_alcumus_going_crazy
15 replies
LittleSnake____
Today at 5:22 AM
Craftybutterfly
5 hours ago
Introducing myself at AoPS, and what's your magic wand?
asuth_asuth   1184
N 6 hours ago by Yihangzh
Hi!

I'm Andrew Sutherland. I'm the new Chief Product Officer at AoPS. As you may have read, Richard is retiring and Ben Kornell and I are working together to lead the company now. I'm leading all the software and digital stuff at AoPS. I just wanted to say hello and introduce myself! I'm really excited to be part of the special community that is AoPS.

Previously, I founded Quizlet as a 15-year-old high school student. I did Course 6 at MIT and then left to lead Quizlet full-time for a total of 14 years. I took a few years off and now I'm doing AoPS! I wrote more about all that on my blog: https://asuth.com/im-joining-aops

I have a question for all of you. If you could wave a magic wand, and change anything about AoPS, what would it be? All suggestions welcome! Thank you.
1184 replies
asuth_asuth
Mar 30, 2025
Yihangzh
6 hours ago
AoPS Volume 1+2
A7456321   2
N Yesterday at 5:33 PM by OGMATH
I've recently been reading the AoPS Volume 1 and 2, and I can't seem to find the answers for any of the exercises. Is there a separate solutions manual I have to buy, or am I just blind and the answers are in the book? Thanks in advance!

EDIT: I couldn't find a forum to post this in so I just posted it in site support. Hope that's ok!
2 replies
A7456321
Yesterday at 5:21 PM
OGMATH
Yesterday at 5:33 PM
All Topics Marked
alpha31415   1
N Friday at 6:10 PM by jmr2010
Excuse me!
for I am a frashman in aops.I wonder how I could get back to mark all my read.All topics in the forum became as if they had been marked.Would someone please help me deal with it???
1 reply
alpha31415
Friday at 12:39 PM
jmr2010
Friday at 6:10 PM
k Hieroglyph (and Petroglyph?) on Post #1
awesomeming327.   10
N Apr 28, 2025 by bpan2021
Steps to Reproduce:
1. Click this link
2. Scroll up.
Behavior: it should show two copies of a certain "post #0" above post #1.
Frequency: 100%

Mac OS, Arc Browser (which runs on Chromium)

Note: you can also click on "view topic" on the N7 of the 2023 ISL
10 replies
awesomeming327.
Apr 27, 2025
bpan2021
Apr 28, 2025
Hieroglyph (and Petroglyph?) on Post #1
G H J
G H BBookmark kLocked kLocked NReply
The post below has been deleted. Click to close.
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awesomeming327.
1721 posts
#1 • 1 Y
Y by RainbowJessa
Steps to Reproduce:
1. Click this link
2. Scroll up.
Behavior: it should show two copies of a certain "post #0" above post #1.
Frequency: 100%

Mac OS, Arc Browser (which runs on Chromium)

Note: you can also click on "view topic" on the N7 of the 2023 ISL
Z Y
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jkim0656
1032 posts
#2 • 1 Y
Y by RainbowJessa
can reproduce
Z Y
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MrMustache
3033 posts
#3 • 2 Y
Y by RainbowJessa, engineer48
can reproduce

what the sigma is that
Z Y
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ostriches88
1535 posts
#4 • 1 Y
Y by RainbowJessa
https://artofproblemsolving.com/community/c10h3404915

unsure why there are two copies but

EDIT: the two posts seem to have ids 32267440 and 32267433 respectively, so maybe it was an accidental double post (or there is a minor edit between the two posts, I haven't actually checked if the contents are completely identical)

EDIT 2: a similar error seems to have occurred on this thread, with the two top posts being IDs 32267441 and 32267434, however this is not reproduceable on any of the other threads that this issue has occurred on (all but one of which happen to all have occurred on different threads in the Mafia! forum, how apt)

EDIT 3: last one xd, the Pokemon thread that I linked in edit 2 does not actually allow you to see the glitched posts simply by scrolling up, you have to directly link to the post, which probably also explains why the thread never stops loading when you access it normally lol
This post has been edited 3 times. Last edited by ostriches88, Apr 27, 2025, 6:30 PM
Z Y
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Biglion
59 posts
#5 • 1 Y
Y by RainbowJessa
These two happened on the same time, and the same date!
Z Y
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bpan2021
2653 posts
#6 • 1 Y
Y by RainbowJessa
This issue is caused by site maintenance on Sep 3, 2024, from 10:30 to 12:40 PM ET. This maintenance brought a lot of problems, and this was one of them.

This issue has been reported before [1] [2] (and the exact post you're talking about was reported here). The issue should have been "passed on to the Engineering team" already.
This post has been edited 4 times. Last edited by bpan2021, Apr 27, 2025, 7:19 PM
Z Y
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MrMustache
3033 posts
#7 • 1 Y
Y by RainbowJessa
nice job super sleuths
Z Y
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Craftybutterfly
522 posts
#8 • 1 Y
Y by RainbowJessa
This has also happened in this thread: https://artofproblemsolving.com/community/c7h3544981. I have no idea how that happened though.
This post has been edited 1 time. Last edited by Craftybutterfly, Apr 28, 2025, 7:04 AM
Z Y
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bpan2021
2653 posts
#9 • 1 Y
Y by RainbowJessa
I do not see a post #0 in that thread. Is there another issue?
Z Y
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Dragon_Yang
299 posts
#10 • 1 Y
Y by RainbowJessa
this is wierd.

bpan2021 where do you get that knowledge
Z Y
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bpan2021
2653 posts
#11 • 2 Y
Y by RainbowJessa, Speedysolver1
It was an educated guess based on the collective knowledge of what happened, but it was confirmed that the site was down at that time.
This post has been edited 1 time. Last edited by bpan2021, Apr 28, 2025, 7:06 PM
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