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k a April Highlights and 2025 AoPS Online Class Information
jlacosta   0
Apr 2, 2025
Spring is in full swing and summer is right around the corner, what are your plans? At AoPS Online our schedule has new classes starting now through July, so be sure to keep your skills sharp and be prepared for the Fall school year! Check out the schedule of upcoming classes below.

WOOT early bird pricing is in effect, don’t miss out! If you took MathWOOT Level 2 last year, no worries, it is all new problems this year! Our Worldwide Online Olympiad Training program is for high school level competitors. AoPS designed these courses to help our top students get the deep focus they need to succeed in their specific competition goals. Check out the details at this link for all our WOOT programs in math, computer science, chemistry, and physics.

Looking for summer camps in math and language arts? Be sure to check out the video-based summer camps offered at the Virtual Campus that are 2- to 4-weeks in duration. 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 events:
[list][*]April 3rd (Webinar), 4pm PT/7:00pm ET, Learning with AoPS: Perspectives from a Parent, Math Camp Instructor, and University Professor
[*]April 8th (Math Jam), 4:30pm PT/7:30pm ET, 2025 MATHCOUNTS State Discussion
April 9th (Webinar), 4:00pm PT/7:00pm ET, Learn about Video-based Summer Camps at the Virtual Campus
[*]April 10th (Math Jam), 4:30pm PT/7:30pm ET, 2025 MathILy and MathILy-Er Math Jam: Multibackwards Numbers
[*]April 22nd (Webinar), 4:00pm PT/7:00pm ET, Competitive Programming at AoPS (USACO).[/list]
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0 replies
jlacosta
Apr 2, 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
1234th Post!
PikaPika999   103
N 6 minutes ago by Pengu14
I hit my 1234th post! (I think I missed it, I'm kinda late, :oops_sign:)

But here's a puzzle for you all! Try to create the numbers 1 through 25 using the numbers 1, 2, 3, and 4! You are only allowed to use addition, subtraction, multiplication, division, and parenthesis. If you're post #1, try to make 1. If you're post #2, try to make 2. If you're post #3, try to make 3, and so on. If you're a post after 25, then I guess you can try to make numbers greater than 25 but you can use factorials, square roots, and that stuff. Have fun!

1: $(4-3)\cdot(2-1)$
103 replies
PikaPika999
3 hours ago
Pengu14
6 minutes ago
GCD Functional Equation
pinetree1   61
N 39 minutes ago by ihategeo_1969
Source: USA TSTST 2019 Problem 7
Let $f: \mathbb Z\to \{1, 2, \dots, 10^{100}\}$ be a function satisfying
$$\gcd(f(x), f(y)) = \gcd(f(x), x-y)$$for all integers $x$ and $y$. Show that there exist positive integers $m$ and $n$ such that $f(x) = \gcd(m+x, n)$ for all integers $x$.

Ankan Bhattacharya
61 replies
pinetree1
Jun 25, 2019
ihategeo_1969
39 minutes ago
An easy FE
oVlad   3
N an hour ago by jasperE3
Source: Romania EGMO TST 2017 Day 1 P3
Determine all functions $f:\mathbb R\to\mathbb R$ such that \[f(xy-1)+f(x)f(y)=2xy-1,\]for any real numbers $x{}$ and $y{}.$
3 replies
oVlad
Today at 1:36 PM
jasperE3
an hour ago
Interesting F.E
Jackson0423   12
N an hour ago by jasperE3
Show that there does not exist a function
\[
f : \mathbb{R}^+ \to \mathbb{R}
\]satisfying the condition that for all \( x, y \in \mathbb{R}^+ \),
\[
f(x + y^2) \geq f(x) + y.
\]

~Korea 2017 P7
12 replies
Jackson0423
Apr 18, 2025
jasperE3
an hour ago
p^3 divides (a + b)^p - a^p - b^p
62861   49
N an hour ago by Ilikeminecraft
Source: USA January TST for IMO 2017, Problem 3
Prove that there are infinitely many triples $(a, b, p)$ of positive integers with $p$ prime, $a < p$, and $b < p$, such that $(a + b)^p - a^p - b^p$ is a multiple of $p^3$.

Noam Elkies
49 replies
62861
Feb 23, 2017
Ilikeminecraft
an hour ago
Bogus Proof Marathon
pifinity   7606
N an hour ago by Pengu14
Hi!
I'd like to introduce the Bogus Proof Marathon.

In this marathon, simply post a bogus proof that is middle-school level and the next person will find the error. You don't have to post the real solution :P

Use classic Marathon format:
[hide=P#]a1b2c3[/hide]
[hide=S#]a1b2c3[/hide]


Example posts:

P(x)
-----
S(x)
P(x+1)
-----
Let's go!! Just don't make it too hard!
7606 replies
pifinity
Mar 12, 2018
Pengu14
an hour ago
3D geometry theorem
KAME06   0
an hour ago
Let $M$ a point in the space and $G$ the centroid of a tetrahedron $ABCD$. Prove that:
$$\frac{1}{4}(AB^2+AC^2+AD^2+BC^2+BD^2+CD^2)+4MG^2=MA^2+MB^2+MC^2+MD^2$$
0 replies
KAME06
an hour ago
0 replies
Funny easy transcendental geo
qwerty123456asdfgzxcvb   1
N an hour ago by golue3120
Let $\mathcal{S}$ be a logarithmic spiral centered at the origin (ie curve satisfying for any point $X$ on it, line $OX$ makes a fixed angle with the tangent to $\mathcal{S}$ at $X$). Let $\mathcal{H}$ be a rectangular hyperbola centered at the origin, scaled such that it is tangent to the logarithmic spiral at some point.

Prove that for a point $P$ on the spiral, the polar of $P$ wrt. $\mathcal{H}$ is tangent to the spiral.
1 reply
qwerty123456asdfgzxcvb
4 hours ago
golue3120
an hour ago
domino question
kjhgyuio   0
2 hours ago
........
0 replies
kjhgyuio
2 hours ago
0 replies
demonic monic polynomial problem
iStud   0
2 hours ago
Source: Monthly Contest KTOM April P4 Essay
(a) Let $P(x)$ be a monic polynomial so that there exists another real coefficients $Q(x)$ that satisfy
\[P(x^2-2)=P(x)Q(x)\]Determine all complex roots that are possible from $P(x)$
(b) For arbitrary polynomial $P(x)$ that satisfies (a), determine whether $P(x)$ should have real coefficients or not.
0 replies
iStud
2 hours ago
0 replies
fun set problem
iStud   0
2 hours ago
Source: Monthly Contest KTOM April P2 Essay
Given a set $S$ with exactly 9 elements that is subset of $\{1,2,\dots,72\}$. Prove that there exist two subsets $A$ and $B$ that satisfy the following:
- $A$ and $B$ are non-empty subsets from $S$,
- the sum of all elements in each of $A$ and $B$ are equal, and
- $A\cap B$ is an empty subset.
0 replies
iStud
2 hours ago
0 replies
two tangent circles
KPBY0507   3
N 2 hours ago by Sanjana42
Source: FKMO 2021 Problem 5
The incenter and $A$-excenter of $\triangle{ABC}$ is $I$ and $O$. The foot from $A,I$ to $BC$ is $D$ and $E$. The intersection of $AD$ and $EO$ is $X$. The circumcenter of $\triangle{BXC}$ is $P$.
Show that the circumcircle of $\triangle{BPC}$ is tangent to the $A$-excircle if $X$ is on the incircle of $\triangle{ABC}$.
3 replies
KPBY0507
May 8, 2021
Sanjana42
2 hours ago
Area of Polygon
AIME15   48
N 3 hours ago by anticodon
The area of polygon $ ABCDEF$, in square units, is

IMAGE

\[ \textbf{(A)}\ 24 \qquad
\textbf{(B)}\ 30 \qquad
\textbf{(C)}\ 46 \qquad
\textbf{(D)}\ 66 \qquad
\textbf{(E)}\ 74
\]
48 replies
1 viewing
AIME15
Jan 12, 2009
anticodon
3 hours ago
9 AMC 8 Scores
ChromeRaptor777   104
N 3 hours ago by GallopingUnicorn45
As far as I'm certain, I think all AMC8 scores are already out. Vote above.
104 replies
ChromeRaptor777
Apr 1, 2022
GallopingUnicorn45
3 hours ago
9 MATHCOUNTS STATE difficulty
Eddie_tiger   67
N Apr 4, 2025 by DhruvJha
I personally thought the problems were much easier than last year, but I didn't really improve as much as I would of liked to improve.
67 replies
Eddie_tiger
Apr 1, 2025
DhruvJha
Apr 4, 2025
MATHCOUNTS STATE difficulty
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G H BBookmark kLocked kLocked NReply
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tikachaudhuri
28 posts
#54
Y by
I thought the test was easier but it could also be because I was dumb last year
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RocketScientist
341 posts
#55
Y by
giratina3 wrote:
The difficulty jump from 2024 Mathcounts State to 2025 Mathcounts State was insane.

Do you mean difficulty drop? This year was much easier, but I feel like the problems were better last year.
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Inaaya
291 posts
#56
Y by
me who didn't qual for states last year
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giratina3
494 posts
#57
Y by
RocketScientist wrote:
giratina3 wrote:
The difficulty jump from 2024 Mathcounts State to 2025 Mathcounts State was insane.

Do you mean difficulty drop? This year was much easier, but I feel like the problems were better last year.

Yeah, that was what I meant by drop. Bro, the problems were so much better last year.
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mathkiddus
226 posts
#58
Y by
ethan2011 wrote:
achunaar000 wrote:
How did you guys do 27

Cheese it by assuming it’s a rectangle

buh, my friend gave me problem and cheesing it into 1 line works :skull: its just subtraction
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lily2030
595 posts
#59
Y by
A LOT of people at my states guessed target 8 right cause you just reverse the probability
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Mathematicalprodigy37
19 posts
#60
Y by
lily2030 wrote:
A LOT of people at my states guessed target 8 right cause you just reverse the probability

I used reverse linearity of expectation and cheesed but you could probably do that to.
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Mathematicalprodigy37
19 posts
#61
Y by
jb2015007 wrote:
i voted a little easier since the problems were much easier than last time but WAYYYY MORE SILLYABLE
Agreed. As a PROFFESSIONAL SILLIER, this test was really inconvenient for me :(
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DhruvJha
845 posts
#62
Y by
Mathematicalprodigy37 wrote:
jb2015007 wrote:
i voted a little easier since the problems were much easier than last time but WAYYYY MORE SILLYABLE
Agreed. As a PROFFESSIONAL SILLIER, this test was really inconvenient for me :(

orz
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EightYearLetterman
14 posts
#63
Y by
orangebear wrote:
There is a kid in my state (PA) who might make nationals who has autism (Has there ever been a kid with autism who made Nats?)

being someone diagnosed as likely on the spectrum I would estimate 1,000-5,000 people on the spectrum have gone to nats. It makes many aspects of life more challenging but on average it probably makes it easier to succeed in math competition.
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EightYearLetterman
14 posts
#64
Y by
DhruvJha wrote:
Andyluo wrote:
I agree with @above.

Mathcounts has had a much worse quality compared to last year.

The school test was very formulaic/unoriginal and just a bad problem set (however not too far off from a school test, just bad)

---

The chapter test was really really bad. The target problem set had to be the worst I've ever seen, with absolutely trivial questions 1-7, and an impossible p8.

----

The state test was just bad compared to last year, and the target test was really bad.

Target problems just felt unoriginal, and were guessable (p6 and p8) which led to a bad test to determine national qualifiers.

Sprint 1-25 weren't terrible, but problems 26-30 were just bad?

I mean what was problem 26 and problem 29
imo the other questions weren't too bad, but again the sprint round was a lot easier than last year

hpfly they make up for it at nats

Can anyone name a national test from 2024 AMC-10B to present that is harder than its counterpart from the previous year? It's becoming a thing...
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Akang11
36 posts
#65
Y by
Honestly that's pretty fair
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SpeedCuber7
1814 posts
#66
Y by
these problem writers bro

did maa cut their wage to minimum because my god these tests have sucked
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K124659
2543 posts
#67
Y by
giratina3 wrote:
The difficulty jump from 2024 Mathcounts State to 2025 Mathcounts State was insane.

2025 mathcounts state was coughing baby compared to 2024
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DhruvJha
845 posts
#68
Y by
K124659 wrote:
giratina3 wrote:
The difficulty jump from 2024 Mathcounts State to 2025 Mathcounts State was insane.

2025 mathcounts state was coughing baby compared to 2024

I mocked in just now and got a 36. In context I got a 25 last year at states and 19 at nats and have not practiced in a year. Why


first 20 on sprint, 26, 22

1,2,3,4,5,7,8 on target

why was this so easy
This post has been edited 3 times. Last edited by DhruvJha, Apr 4, 2025, 8:44 PM
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