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Contests & Programs AMC and other contests, summer programs, etc.
AMC and other contests, summer programs, etc.
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Contests & Programs AMC and other contests, summer programs, etc.
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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.

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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
Lines pass through a common point
April   5
N 41 minutes ago by SatisfiedMagma
Source: Baltic Way 2008, Problem 18
Let $ AB$ be a diameter of a circle $ S$, and let $ L$ be the tangent at $ A$. Furthermore, let $ c$ be a fixed, positive real, and consider all pairs of points $ X$ and $ Y$ lying on $ L$, on opposite sides of $ A$, such that $ |AX|\cdot |AY| = c$. The lines $ BX$ and $ BY$ intersect $ S$ at points $ P$ and $ Q$, respectively. Show that all the lines $ PQ$ pass through a common point.
5 replies
April
Nov 23, 2008
SatisfiedMagma
41 minutes ago
Parameter and 4 variables
mihaig   1
N an hour ago by mihaig
Source: Own
Find the positive real constants $K$ such that
$$3\left(a^2+b^2+c^2+d^2\right)+4\left(abcd\right)^K\geq\left(a+b+c+d\right)^2$$for all $a,b,c,d\geq0$ satisfying $a+b+c+d\geq4.$
1 reply
mihaig
an hour ago
mihaig
an hour ago
Old Inequality
giangtruong13   0
an hour ago
Let $a,b,c >0$ and $abc=1$. Prove that: $$  \sqrt{a^2-a+1}+\sqrt{b^2-b+1} +\sqrt{c^2-c+1} \ge a+b+c$$
0 replies
giangtruong13
an hour ago
0 replies
How many friends can sit in that circle at most?
Arytva   0
an hour ago

A group of friends sits in a ring. Each friend picks a different whole number and holds a stone marked with it. Then they pass their stone one seat to the right so everyone ends up with two stones: one they made and one they received. Now they notice something odd: if your original number is $x$, your right-neighbor’s is $y$, and the next person over is $z$, then for every trio in the circle they see

$$
x + z = (2 - x)\,y.
$$
They want as many friends as possible before this breaks (since all stones must stay distinct).

How many friends can sit in that circle at most?
0 replies
Arytva
an hour ago
0 replies
Reflected point lies on radical axis
Mahdi_Mashayekhi   7
N an hour ago by amogususususus
Source: Iran 2025 second round P4
Given is an acute and scalene triangle $ABC$ with circumcenter $O$. $BO$ and $CO$ intersect the altitude from $A$ to $BC$ at points $P$ and $Q$ respectively. $X$ is the circumcenter of triangle $OPQ$ and $O'$ is the reflection of $O$ over $BC$. $Y$ is the second intersection of circumcircles of triangles $BXP$ and $CXQ$. Show that $X,Y,O'$ are collinear.
7 replies
Mahdi_Mashayekhi
Apr 19, 2025
amogususususus
an hour ago
Shortlist 2017/G3
fastlikearabbit   124
N an hour ago by ND_
Source: Shortlist 2017, Moldova TST 2018
Let $O$ be the circumcenter of an acute triangle $ABC$. Line $OA$ intersects the altitudes of $ABC$ through $B$ and $C$ at $P$ and $Q$, respectively. The altitudes meet at $H$. Prove that the circumcenter of triangle $PQH$ lies on a median of triangle $ABC$.
124 replies
fastlikearabbit
Jul 10, 2018
ND_
an hour ago
Is there a good solution?
sadwinter   0
an hour ago
:maybe: :love: :love:
0 replies
sadwinter
an hour ago
0 replies
Factoring 2024 in Z[\sqrt{3}]
Tintarn   2
N an hour ago by Rayholr123
Source: Czech-Polish-Slovak Junior Match 2024, T-2
Among all triples $(a,b,c)$ of natural numbers satisfying
\[(a+14\sqrt{3})(b-14c\sqrt{3})=2024,\]determine the one with the maximal value of $a$.
2 replies
Tintarn
May 29, 2024
Rayholr123
an hour ago
Inspired by old results
sqing   2
N an hour ago by sqing
Source: Own
Let $ a,b> 0. $ Prove that
$$  \frac{a^3}{b^3+ab^2}+ \frac{4b^3}{a^3+b^3+2ab^2}\geq \frac{3}{2}$$$$\frac{a^3}{b^3+(a+b)^3}+ \frac{b^3}{a^3+(a+b)^3}+ \frac{(a+b)^2}{a^2+b^2+ab} \geq \frac{14}{9}$$
2 replies
sqing
Today at 2:55 AM
sqing
an hour ago
Interesting inequality
sqing   4
N an hour ago by sqing
Source: Own
Let $ a,b,c\geq  0 , a^2+b^2+c^2 =3.$ Prove that
$$ a^4+ b^4+c^4+6abc\leq9$$$$ a^3+ b^3+  c^3+3( \sqrt{3}-1)abc\leq 3\sqrt 3$$
4 replies
sqing
Yesterday at 2:54 AM
sqing
an hour ago
AIME qual outside US?
daijobu   11
N Today at 2:59 AM by CatCatHead
Can students outside the US take the AIME if they earn a qualifying score?
11 replies
daijobu
Friday at 7:10 PM
CatCatHead
Today at 2:59 AM
Mustang Math Recruitment is Open!
MustangMathTournament   8
N Today at 2:54 AM by Henry2020
The Interest Form for joining Mustang Math is open!

Hello all!

We're Mustang Math, and we are currently recruiting for the 2025-2026 year! If you are a high school or college student and are passionate about promoting an interest in competition math to younger students, you should strongly consider filling out the following form: https://link.mustangmath.com/join. Every member in MM truly has the potential to make a huge impact, no matter your experience!

About Mustang Math

Mustang Math is a nonprofit organization of high school and college volunteers that is dedicated to providing middle schoolers access to challenging, interesting, fun, and collaborative math competitions and resources. Having reached over 4000 U.S. competitors and 1150 international competitors in our first six years, we are excited to expand our team to offer our events to even more mathematically inclined students.

PROJECTS
We have worked on various math-related projects. Our annual team math competition, Mustang Math Tournament (MMT) recently ran. We hosted 8 in-person competitions based in Washington, NorCal, SoCal, Illinois, Georgia, Massachusetts, Nevada and New Jersey, as well as an online competition run nationally. In total, we had almost 900 competitors, and the students had glowing reviews of the event. MMT International will once again be running later in August, and with it, we anticipate our contest to reach over a thousand students.

In our classes, we teach students math in fun and engaging math lessons and help them discover the beauty of mathematics. Our aspiring tech team is working on a variety of unique projects like our website and custom test platform. We also have a newsletter, which, combined with our social media presence, helps to keep the mathematics community engaged with cool puzzles, tidbits, and information about the math world! Our design team ensures all our merch and material is aesthetically pleasing.

Some highlights of this past year include 1000+ students in our classes, AMC10 mock with 150+ participants, our monthly newsletter to a subscriber base of 6000+, creating 8 designs for 800 pieces of physical merchandise, as well as improving our custom website (mustangmath.com, 20k visits) and test-taking platform (comp.mt, 6500+ users).

Why Join Mustang Math?

As a non-profit organization on the rise, there are numerous opportunities for volunteers to share ideas and suggest projects that they are interested in. Through our organizational structure, members who are committed have the opportunity to become a part of the leadership team. Overall, working in the Mustang Math team is both a fun and fulfilling experience where volunteers are able to pursue their passion all while learning how to take initiative and work with peers. We welcome everyone interested in joining!

More Information

To learn more, visit https://link.mustangmath.com/RecruitmentInfo. If you have any questions or concerns, please email us at contact@mustangmath.com.

https://link.mustangmath.com/join
8 replies
MustangMathTournament
May 24, 2025
Henry2020
Today at 2:54 AM
MOP Emails Out! (not clickbait)
Mathandski   106
N Today at 2:32 AM by CheerfulZebra68
What an emotional roller coaster the past 34 days have been.

Congrats to all that qualified!
106 replies
Mathandski
Apr 22, 2025
CheerfulZebra68
Today at 2:32 AM
BIG BEEF BETWEEN MATHMATICANS (EXPOSED!!!!!) [MathEXplained Magazine]
yolk_eggg   0
Today at 2:17 AM
Source: https://mathexplained.github.io/
Hey AOPS!!!!! :D :D :D :D :D

Hope you're all excited for the summer! As the summer approaches and you're all beginning to get back on the math grind I hope that you'll all also do some leisurely math reading/discovery!!

Check out this month's MathEXplained Magazine issue where we explore:
1. The math behind sports betting
2. The birthday paradox
3. Mathematicians born in May and their contributions to math
4. The ulam spiral
5. The surprising past behind the cubic formula (INSANE BEEF)

You can read this months issue on our website at https://mathexplained.github.io/ or on this google drive file

Additionally, if you are interested in sharing our own niche mathematical interests, I would encourage you to apply for a staff position at: [url][/url]https://tinyurl.com/MEXapply

Don't forget to join our discord server at https://tinyurl.com/MEXplained to let us know who's side you're on!!
0 replies
yolk_eggg
Today at 2:17 AM
0 replies
A weird solar panel
asbodke   54
N Nov 5, 2022 by astingo
Source: 2021 AMC 10A (Fall) #17
An architect is building a structure that will place vertical pillars at the vertices of regular hexagon $ABCDEF$, which is lying horizontally on the ground. The six pillars will hold up a flat solar panel that will not be parallel to the ground. The heights of the pillars at $A$, $B$, and $C$ are $12,9,$ and $10$ meters, respectively. What is the height, in meters, of the pillar at $E$?

$\textbf{(A) }9\qquad\textbf{(B) }6\sqrt3\qquad\textbf{(C) }8\sqrt3\qquad\textbf{(D) }17\qquad\textbf{(E) }12\sqrt3$
54 replies
asbodke
Nov 11, 2021
astingo
Nov 5, 2022
A weird solar panel
G H J
G H BBookmark kLocked kLocked NReply
Source: 2021 AMC 10A (Fall) #17
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awesomeming327.
1742 posts
#41
Y by
I solved this using intuition from vector gradients in a parallelogram.
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astingo
124 posts
#44
Y by
Or is it D?
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Jwenslawski
4344 posts
#45
Y by
astingo wrote:
Or is it D?

Yes it is D.
Please don't spam.
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pieMax2713
4230 posts
#46
Y by
astingo wrote:
Is it :play_ball: :wallbash_red: :wallbash: :gathering: :evilgrin: :diablo:
astingo wrote:
:diablo:

Don't spam.

edit: oof sniped thanks @above
This post has been edited 1 time. Last edited by pieMax2713, Nov 14, 2021, 10:24 PM
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ReaperGod
1579 posts
#47
Y by
pi271828 wrote:
greenturtle3141 wrote:
This was the best problem on the test because it tests your intuition for the "linear nature" of planes.

My solution precisely matches BryanGuo's.

but.... but.... planes don't move in straight lines, then instead of landing in Australia, or India, we would go to space!

plane equations = 3d coordinates
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ike.chen
1162 posts
#51
Y by
greenturtle3141 wrote:
This was the best problem on the test because it tests your intuition for the "linear nature" of planes.

My solution precisely matches BryanGuo's.
Remark: Some people may find it more natural to consider the orthographic projections of points on the solar panel onto the plane containing $ABCDEF$, although this technique might match your interpretation of "the linear nature of planes".
This post has been edited 1 time. Last edited by ike.chen, Nov 15, 2021, 3:13 PM
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megarnie
5611 posts
#52
Y by
Solution 1
Solution 2
This post has been edited 1 time. Last edited by megarnie, Jan 11, 2022, 9:50 PM
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rrc08
767 posts
#53
Y by
This is how I did it. It probably doesn't work but it was fast and it got the right answer.

basically I extended once for every point.
Attachments:
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astingo
124 posts
#54
Y by
D for DUH!
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samrocksnature
8791 posts
#55
Y by
astingo wrote:
D for DUH!

more like deez nuts
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asdf334
7585 posts
#56 • 2 Y
Y by samrocksnature, megarnie
imagine not sillying the problem before this
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dragoon
1947 posts
#57
Y by
imagine saying "17 is too big" and guessing between all the other answer choices before realizing it is 17 afterwards
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brainfertilzer
1831 posts
#58
Y by
use the fact that planes are linear to see that the height of $O$ is $$h_O = h_B + (h_A - h_B) + (h_C - h_B) = 9 + 3 + 1 = 13.$$Also, linearity gives $\frac{h_B + h_E}{2} = h_O$ since $B,O,E$ are collinear. Thus $$h_E = 2h_O - h_B = 26 - 9 = \boxed{17}$$
This post has been edited 1 time. Last edited by brainfertilzer, Oct 31, 2022, 10:24 PM
Reason: adding a legit solution
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OlympusHero
17020 posts
#59
Y by
tenebrine wrote:
We will use coordinates. WLOG let $ABCDEF$ have side length $2$, even though this is bad practice in WLOGing.
Let $B$ be at $(0,0,9)$, and $A$ be at $(2,0,12)$. Then $C$ is at $(-1, \sqrt3, 10)$.
$E$ is at $(2, 2\sqrt3, h)$, where $h$ is the desired height. Note that $A, C, B, E$ must be coplanar.
The equation of a plane is $Ax + By + Cz + D = 0$. WLOG let $D = 9$. Then $C = -1$ by plugging into point $B$, and $A = \frac{3}{2}$ by plugging into point $A$. Plugging in point $C$ gives $B = \frac{5}{2\sqrt{3}}$.
Therefore, $(2, 2\sqrt3, h)$ lies on $\frac32 x + \frac{5}{2\sqrt3}y - z + 9 = 0$. Plugging in gives $3 + 5 + 9 - h = 0$, so $h = \boxed{\textbf{(D) }17}$

This confuses me, with those coordinates isn't the distance $AB$ equal to $\sqrt{13}$ instead of $2$ like it should be?
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astingo
124 posts
#60
Y by
17 boi
:oops:
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