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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

Prealgebra 1 Self-Paced

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Introduction to Counting & Probability Self-Paced

Introduction to Counting & Probability
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0 replies
jlacosta
May 1, 2025
0 replies
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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
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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
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Alcumus Rating
awesometriangles   2
N an hour ago by Craftybutterfly
My Alcumus rating for CP used to be something like a 90, then I went to do some homework for a class, and when I came back to alcumus, it is now a 40. I don't know what happened and I haven't touched C&P in the last hour or two, and I haven't gotten any wrong in it or anything to majorly decrease my rating. I also checked the topics, and each was either green or blue, like how I left it. Is this just me?

EDIT: My level is still the same too..., and idk if i should add an image, and if i should, what should I screenshot?
2 replies
awesometriangles
Today at 1:36 AM
Craftybutterfly
an hour ago
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we can find one pair of a boy and a girl
orl   16
N an hour ago by ezpotd
Source: Vietnam TST 2001 for the 42th IMO, problem 3
Some club has 42 members. It’s known that among 31 arbitrary club members, we can find one pair of a boy and a girl that they know each other. Show that from club members we can choose 12 pairs of knowing each other boys and girls.
16 replies
orl
Jun 26, 2005
ezpotd
an hour ago
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teleporting wizard starts on point (2017, 101), 4 moves
parmenides51   1
N an hour ago by jasperE3
Source: 2018 USAIMEO #2 p5 (Mock AIME -USAJMO) https://artofproblemsolving.com/community/c594864h1572209p9658908
A teleporting wizard starts on the point $(2017, 101)$ and can teleport to other Cartesian coordinates with only $1$ of $4$ moves: $(x, y) \to (x + y, y)$, $(x, y) \to (x - y, y)$ when $x > y$, $(x, y) \to (x, x + y)$, and $(x, y) \to (x, y - x)$ when $y > x$.

(a) Let $P(x)$ be any polynomial with positive integer coefficients that passes through $(0, 0)$. Show that for all such $P(x)$, there exists a unique point on the curve where the wizard can land on.

(b) For each $P(x)$, let $S$ be this unique point. Find the equation of the graph that contains all potential $S$.
1 reply
parmenides51
Nov 17, 2023
jasperE3
an hour ago
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IMO ShortList 2001, combinatorics problem 1
orl   33
N an hour ago by ihategeo_1969
Source: IMO ShortList 2001, combinatorics problem 1
Let $A = (a_1, a_2, \ldots, a_{2001})$ be a sequence of positive integers. Let $m$ be the number of 3-element subsequences $(a_i,a_j,a_k)$ with $1 \leq i < j < k \leq 2001$, such that $a_j = a_i + 1$ and $a_k = a_j + 1$. Considering all such sequences $A$, find the greatest value of $m$.
33 replies
orl
Sep 30, 2004
ihategeo_1969
an hour ago
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CooL geo
Pomegranat   0
2 hours ago
Source: Idk

In triangle \( ABC \), \( D \) is the midpoint of \( BC \). \( E \) is an arbitrary point on \( AC \). Let \( S \) be the intersection of \( AD \) and \( BE \). The line \( CS \) intersects with the circumcircle of \( ACD \), for the second time at \( K \). \( P \) is the circumcenter of triangle \( ABE \). Prove that \( PK \perp CK \).
0 replies
Pomegranat
2 hours ago
0 replies
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Coefficient Problem
P162008   2
N 2 hours ago by cazanova19921
Consider the polynomial $g(x) = \prod_{i=1}^{7} \left(1 + x^{i!} + x^{2i!} + x^{3i!} + \cdots + x^{(i-1)i!} + x^{ii!}\right)$
Find the coefficient of $x^{2025}$ in the expansion of $g(x).$
2 replies
P162008
Yesterday at 12:16 PM
cazanova19921
2 hours ago
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Shooting An Invisible Tank
Aryan27   0
2 hours ago
Source: 239 MO
An invisible tank is on a $100 \times 100 $ table. A cannon can fire at any $k$ cells of the board after that the tank will move to one of the adjacent cells (by side). Then the process is repeated. Find the smallest value of $k$ such that the cannon can definitely shoot the tank after some time.
0 replies
Aryan27
2 hours ago
0 replies
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Showing Tangency
Itoz   1
N 3 hours ago by ja.
Source: Own
The circumcenter of $\triangle ABC$ is $O$. Line $AO$ meets line $BC$ at point $D$, and there is a point $E$ on $\odot(ABC)$ such that $AE \perp BC$. Line $DE$ intersects $\odot(ABC)$ at point $F$. The perpendicular bisector of line segment $BC$ intersects line $AB$ at point $K$, and line $AB$ intersects $\odot(CFK)$ at point $L$.

Prove that $\odot(AFL)$ is tangent to $\odot (OBC)$.
1 reply
Itoz
Yesterday at 1:57 PM
ja.
3 hours ago
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2-var inequality
sqing   7
N 3 hours ago by mathuz
Source: Own
Let $ a,b\geq 0 $. Prove that
$$ \frac{a }{a^2+2b^2+1}+ \frac{b }{b^2+2a^2+1}\leq \frac{1}{\sqrt{3}} $$$$ \frac{a }{2a^2+ b^2+2ab+1}+ \frac{b }{2b^2+ a^2+2ab+1} \leq \frac{1}{\sqrt{5}} $$$$ \frac{a }{2a^2+ b^2+ ab+1}+ \frac{b }{2b^2+ a^2+ ab+1} \leq \frac{1}{2} $$$$\frac{a }{a^2+2b^2+2ab+1}+ \frac{b }{b^2+2a^2+2ab+1}\leq \frac{1}{2} $$
7 replies
sqing
Today at 1:39 AM
mathuz
3 hours ago
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1988 USAMO Problem 4
ahaanomegas   31
N 3 hours ago by LeYohan
Let $I$ be the incenter of triangle $ABC$, and let $A'$, $B'$, and $C'$ be the circumcenters of triangles $IBC$, $ICA$, and $IAB$, respectively. Prove that the circumcircles of triangles $ABC$ and $A'B'C'$ are concentric.
31 replies
ahaanomegas
Jul 27, 2011
LeYohan
3 hours ago
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Introducing myself at AoPS, and what's your magic wand?
asuth_asuth   1158
N 3 hours ago by Craftybutterfly
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.
1158 replies
asuth_asuth
Mar 30, 2025
Craftybutterfly
3 hours ago
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Error in forum
Speedysolver1   3
N 3 hours ago by Craftybutterfly
Will put video
3 replies
Speedysolver1
Apr 23, 2025
Craftybutterfly
3 hours ago
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Reply box disappearing
Craftybutterfly   23
N 3 hours ago by Craftybutterfly
For some reason, on my iPhone XR, when I press on the view my posts button, then press on an unlocked topic and scroll down or press go down button, the reply box disappears. I can’t use the proper format right now as I am on phone.
Summary of the problem: the lines above
setps to reproduce:
1. Go to your profile
2. Press on your posts button
3. press an unlocked topic and scroll down
Frequency: 100%
Browser: Chrome latest version
Device: iPhone XR
23 replies
Craftybutterfly
Apr 30, 2025
Craftybutterfly
3 hours ago
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How many numbers
brokendiamond   0
4 hours ago
How many 5-digit numbers can be formed using the digits 1, 3, 5, 7, 9 such that the smaller digits are not positioned between two larger digits?
0 replies
brokendiamond
4 hours ago
0 replies
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k question
dragonlouis   1
N Apr 8, 2025 by bpan2021
hey, my class just ended. i was wondering if there was any support team I could contact to extend the amount of time I can access the course materials. thanks!
1 reply
dragonlouis
Apr 8, 2025
bpan2021
Apr 8, 2025
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question
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Support
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dragonlouis
583 posts
dragonlouis
#1 h  Apr 8, 2025, 9:31 PM
Y by
hey, my class just ended. i was wondering if there was any support team I could contact to extend the amount of time I can access the course materials. thanks!
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The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
bpan2021
2631 posts
bpan2021
#3 h  Apr 8, 2025, 10:18 PM
Y by
Do not contact that email.
The correct email is student-services@aops.com or student-services@artofproblemsolving.com.
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