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k a My Retirement & New Leadership at AoPS
rrusczyk   1573
N Yesterday at 11:40 PM by SmartGroot
I write today to announce my retirement as CEO from Art of Problem Solving. When I founded AoPS 22 years ago, I never imagined that we would reach so many students and families, or that we would find so many channels through which we discover, inspire, and train the great problem solvers of the next generation. I am very proud of all we have accomplished and I’m thankful for the many supporters who provided inspiration and encouragement along the way. I'm particularly grateful to all of the wonderful members of the AoPS Community!

I’m delighted to introduce our new leaders - Ben Kornell and Andrew Sutherland. Ben has extensive experience in education and edtech prior to joining AoPS as my successor as CEO, including starting like I did as a classroom teacher. He has a deep understanding of the value of our work because he’s an AoPS parent! Meanwhile, Andrew and I have common roots as founders of education companies; he launched Quizlet at age 15! His journey from founder to MIT to technology and product leader as our Chief Product Officer traces a pathway many of our students will follow in the years to come.

Thank you again for your support for Art of Problem Solving and we look forward to working with millions more wonderful problem solvers in the years to come.

And special thanks to all of the amazing AoPS team members who have helped build AoPS. We’ve come a long way from here:IMAGE
1573 replies
+1 w
rrusczyk
Mar 24, 2025
SmartGroot
Yesterday at 11:40 PM
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k a March Highlights and 2025 AoPS Online Class Information
jlacosta   0
Mar 2, 2025
March is the month for State MATHCOUNTS competitions! Kudos to everyone who participated in their local chapter competitions and best of luck to all going to State! Join us on March 11th for a Math Jam devoted to our favorite Chapter competition problems! Are you interested in training for MATHCOUNTS? Be sure to check out our AMC 8/MATHCOUNTS Basics and Advanced courses.

Are you ready to level up with Olympiad training? Registration is open with early bird pricing available for our WOOT programs: MathWOOT (Levels 1 and 2), CodeWOOT, PhysicsWOOT, and ChemWOOT. What is WOOT? WOOT stands for Worldwide Online Olympiad Training and is a 7-month high school math Olympiad preparation and testing program that brings together many of the best students from around the world to learn Olympiad problem solving skills. Classes begin in September!

Do you have plans this summer? There are so many options to fit your schedule and goals whether attending a summer camp or taking online classes, it can be a great break from the routine of the school year. Check out our summer courses at AoPS Online, or if you want a math or language arts class that doesn’t have homework, but is an enriching summer experience, our AoPS Virtual Campus summer camps may be just the ticket! We are expanding our locations for our AoPS Academies across the country with 15 locations so far and new campuses opening in Saratoga CA, Johns Creek GA, and the Upper West Side NY. Check out this page for summer camp information.

Be sure to mark your calendars for the following events:
[list][*]March 5th (Wednesday), 4:30pm PT/7:30pm ET, HCSSiM Math Jam 2025. Amber Verser, Assistant Director of the Hampshire College Summer Studies in Mathematics, will host an information session about HCSSiM, a summer program for high school students.
[*]March 6th (Thursday), 4:00pm PT/7:00pm ET, Free Webinar on Math Competitions from elementary through high school. Join us for an enlightening session that demystifies the world of math competitions and helps you make informed decisions about your contest journey.
[*]March 11th (Tuesday), 4:30pm PT/7:30pm ET, 2025 MATHCOUNTS Chapter Discussion MATH JAM. AoPS instructors will discuss some of their favorite problems from the MATHCOUNTS Chapter Competition. All are welcome!
[*]March 13th (Thursday), 4:00pm PT/7:00pm ET, Free Webinar about Summer Camps at the Virtual Campus. Transform your summer into an unforgettable learning adventure! From elementary through high school, we offer dynamic summer camps featuring topics in mathematics, language arts, and competition preparation - all designed to fit your schedule and ignite your passion for learning.[/list]
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0 replies
jlacosta
Mar 2, 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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NT problem
nhathhuyyp5c   0
10 minutes ago
Let \( S \) be the set of all pairs \( (k, m) \) satisfying the conditions: \( k, m \) are positive integers with \( k > m \) and
\[ k^3 - m^3 \mid km(k^2 - m^2). \]Find the largest real number \( c \) such that
\[ (k - m)^3 \geq ckm \]for all \( (k, m) \in S \).
0 replies
nhathhuyyp5c
10 minutes ago
0 replies
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Intersecting diagonals in an n-gon
61plus   14
N 44 minutes ago by zRevenant
Source: All Russian-2014 Grade 9 Day 1 P3
In a convex $n$-gon, several diagonals are drawn. Among these diagonals, a diagonal is called good if it intersects exactly one other diagonal drawn (in the interior of the $n$-gon). Find the maximum number of good diagonals.
14 replies
61plus
May 17, 2014
zRevenant
44 minutes ago
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An inequality
JK1603JK   1
N an hour ago by lbh_qys
Let a,b,c\ge 0: a+b+c>0 then prove \frac{a^{2}+bc}{b+c+2a}+\frac{b^{2}+ca}{c+a+2b}+\frac{c^{2}+ab}{a+b+2c}\ge \frac{a+b+c}{2}
1 reply
JK1603JK
an hour ago
lbh_qys
an hour ago
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2015 Paraguayan Mathematical Olympiad: Problem 2 - Level 2
Mualpha7   2
N an hour ago by Lyeon
Source: Level 2 : 8th and 9th Grades
Consider numbers of the form $1a1$, where $a$ is a digit. How many pairs of such numbers are there such that their sum is also a palindrome?

Note: A palindrome is a number which reads the same from left to right and from right to left. Examples: $353$, $91719$.
2 replies
Mualpha7
Oct 10, 2015
Lyeon
an hour ago
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An inequality
jokehim   5
N 2 hours ago by lbh_qys
Let $a,b,c \in \mathbb{R}: a+b+c=3$ then prove $$\color{black}{\frac{a^2}{a^{2}-2a+3}+\frac{b^2}{b^{2}-2b+3}+\frac{c^2}{c^{2}-2c+3}\ge \frac{3}{2}.}$$
5 replies
jokehim
Mar 21, 2025
lbh_qys
2 hours ago
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D1018 : Can you do that ?
Dattier   1
N 2 hours ago by Dattier
Source: les dattes à Dattier
We can find $A,B,C$, such that $\gcd(A,B)=\gcd(C,A)=\gcd(A,2)=1$ and $$\forall n \in \mathbb N^*, (C^n \times B \mod A) \mod 2=0 $$.

For example :

$C=20$
$A=47650065401584409637777147310342834508082136874940478469495402430677786194142956609253842997905945723173497630499054266092849839$

$B=238877301561986449355077953728734922992395532218802882582141073061059783672634737309722816649187007910722185635031285098751698$

Can you find $A,B,C$ such that $A>3$ is prime, $C,B \in (\mathbb Z/A\mathbb Z)^*$ with $o(C)=(A-1)/2$ and $$\forall n \in \mathbb N^*, (C^n \times B \mod A) \mod 2=0 $$?
1 reply
Dattier
Mar 24, 2025
Dattier
2 hours ago
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inequality
pennypc123456789   1
N 2 hours ago by lbh_qys
Given that \( a, b, c \) are real numbers satisfying the inequality
\[ (a+3c)(a+2b+3c) < 0, \]prove that
\[ (2b-3c)^2 > 4a(a+2b+3c). \]
1 reply
pennypc123456789
4 hours ago
lbh_qys
2 hours ago
J
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Inequality with factorial !
Virgil Nicula   2
N 2 hours ago by Snoop76
Prove that for any $ n\in N^{*}$we have $ \boxed{\ \left(\frac{n}{n+1}\right)^{n+1}<\sqrt [n+1]{(n+1) !}-\sqrt [n]{n!}\ }$
2 replies
Virgil Nicula
Sep 18, 2007
Snoop76
2 hours ago
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concyclic wanted, 2 circles tangent to incircle related
parmenides51   7
N 3 hours ago by Ihatecombin
Source: Hong Kong TST - HKTST 2024 1.6
Let $\Omega$ be the incircle of $\Delta ABC$. There are two smaller circles $\omega_1$ amd $\omega_2$ inside $\Delta ABC$. The circle $\omega_1$ is tangent to $\Omega$ at $P$, tangent to $BC$ at $D$, and also tangent to $AB$. The circle $\omega_2$ is tangent to $\Omega$ at $Q$, tangent to $BC$ at $E$, and also tangent to $AC$. Prove that $D,E,Q,P$ are concyclic.
7 replies
parmenides51
Jul 20, 2024
Ihatecombin
3 hours ago
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Number Theory Problem in Taiwan TST
chengbilly   1
N 3 hours ago by vi144
Source: 2025 Taiwan TST Round 2 Independent Study 2-N
Find all prime number pairs $(p, q)$ such that \[p^q+q^p+p+q-5pq\]is a perfect square.

Proposed by chengbilly
1 reply
chengbilly
5 hours ago
vi144
3 hours ago
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Inequality
Tendo_Jakarta   0
3 hours ago
Let \(a,b,c\) be positive numbers such that \(a+b+c = 3\). Find the maximum value of
\[T = \dfrac{bc}{\sqrt{a}+3}+\dfrac{ca}{\sqrt{b}+3}+\dfrac{ab}{\sqrt{c}+3} \]
0 replies
1 viewing
Tendo_Jakarta
3 hours ago
0 replies
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Geometry Problem in Taiwan TST
chengbilly   2
N 4 hours ago by Li4
Source: 2025 Taiwan TST Round 2 Independent Study 2-G
Given a triangle $ABC$ with circumcircle $\Gamma$, and two arbitrary points $X, Y$ on $\Gamma$. Let $D$, $E$, $F$ be points on lines $BC$, $CA$, $AB$, respectively, such that $AD$, $BE$, and $CF$ concur at a point $P$. Let $U$ be a point on line $BC$ such that $X$, $Y$, $D$, $U$ are concyclic. Similarly, let $V$ be a point on line $CA$ such that $X$, $Y$, $E$, $V$ are concyclic, and let $W$ be a point on line $AB$ such that $X$, $Y$, $F$, $W$ are concyclic. Prove that $AU$, $BV$, $CW$ concur at a single point.

Proposed by chengbilly
2 replies
chengbilly
6 hours ago
Li4
4 hours ago
J
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Something nice
KhuongTrang   24
N 4 hours ago by Nguyenhuyen_AG
Source: own
Problem. Given $a,b,c$ be non-negative real numbers such that $ab+bc+ca=1.$ Prove that

$$\sqrt{a+1}+\sqrt{b+1}+\sqrt{c+1}\le 1+2\sqrt{a+b+c+abc}.$$
24 replies
KhuongTrang
Nov 1, 2023
Nguyenhuyen_AG
4 hours ago
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a+b+c=3 inequality
jokehim   0
4 hours ago
Source: my problem
Let $a,b,c\ge 0: a+b+c=3.$ Prove that $$a\sqrt{bc+3}+b\sqrt{ca+3}+c\sqrt{ab+3}\ge \sqrt{12(ab+bc+ca)}.$$
0 replies
jokehim
4 hours ago
0 replies
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J
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Inequality
MathsII-enjoy   1
N Tuesday at 12:13 PM by sqing
A good inequality problem :coolspeak:
1 reply
MathsII-enjoy
Tuesday at 11:00 AM
sqing
Tuesday at 12:13 PM
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Inequality
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Reveal topic tags
inequalities
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MathsII-enjoy
6 posts
MathsII-enjoy
#1 h  Tuesday at 11:00 AM
Y by
A good inequality problem :coolspeak:
Attachments:
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sqing
41273 posts
sqing
#2 h  Tuesday at 12:13 PM
Y by
Let $a,b,c$ be real numbers.Prove that$$(a^2-a+1)(b^2-b+1)(c^2-c+1)\ge (a-b) (b-c) (c-a)$$https://artofproblemsolving.com/community/c6h462983p2597101
https://artofproblemsolving.com/community/c6h4830p8689629
This post has been edited 1 time. Last edited by sqing, Tuesday at 12:14 PM
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