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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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I need help!-tpulak
tpulak   9
N 3 minutes ago by Andyluo
Hello peoples:
I need help on a problem. If you know the solution, could you please post it, and tell me how to do it? Here is the problem:
"The product (66)(9)(22)(39) has a prime factorization of the form (2A)(3B)(11C)(13D). What is the value of ac-bd? "

{Note: 2a actually represents "2 to the power of a", same goes for 3b,11c, & 13D}

PLEASE HELP ME! :?: :!: :!: :!:
9 replies
tpulak
Nov 30, 2007
Andyluo
3 minutes ago
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Flag poles
chess64   7
N 44 minutes ago by ohiorizzler1434
Source: Canada 1971, Problem 9
Two flag poles of height $h$ and $k$ are situated $2a$ units apart on a level surface. Find the set of all points on the surface which are so situated that the angles of elevation of the tops of the poles are equal.
7 replies
chess64
Jun 24, 2006
ohiorizzler1434
44 minutes ago
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Greece JBMO TST
ultralako   24
N an hour ago by ali123456
Source: Greece JBMO TST Problem 4
Find all positive integers $x,y,z$ with $z$ odd, which satisfy the equation:

$$2018^x=100^y + 1918^z$$
24 replies
ultralako
Apr 22, 2018
ali123456
an hour ago
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Need some help on this problem please?
tpulak   7
N an hour ago by DhruvJha
What is the number of distinct lines representing the altitudes, medians, and interior angle bisectors of a triangle that is isosceles, but not equilateral?

Please tell me an explanation if you can solve
7 replies
tpulak
Feb 18, 2010
DhruvJha
an hour ago
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How important is math "intuition"
Dream9   7
N an hour ago by BS2012
When I see problems now, they usually fall under 3 categories: easy, annoying, and cannot solve. Over time, more problems become easy, but I don't think I'm learning anything "new" so is higher level math like AMC 10 more about practice, so you know what to do when you see a problem? Of course, there's formulas for some problems but when reading a lot of solutions I didn't see many weird formulas being used and it was just the way to solve the problem was "odd".
7 replies
Dream9
Today at 2:16 PM
BS2012
an hour ago
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f(x^2 + f(y)) = y + (f(x))^2
orl   55
N an hour ago by KAME06
Source: IMO 1992, Day 1, Problem 2
Let $\,{\mathbb{R}}\,$ denote the set of all real numbers. Find all functions $\,f: {\mathbb{R}}\rightarrow {\mathbb{R}}\,$ such that \[ f\left( x^{2}+f(y)\right) =y+\left( f(x)\right) ^{2}\hspace{0.2in}\text{for all}\,x,y\in \mathbb{R}. \]
55 replies
orl
Nov 11, 2005
KAME06
an hour ago
J
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Cool Number Theory
Fermat_Fanatic108   8
N an hour ago by BR1F1SZ
For an integer with 5 digits $n=abcde$ (where $a, b, c, d, e$ are the digits and $a\neq 0$) we define the \textit{permutation sum} as the value $$bcdea+cdeab+deabc+eabcd$$For example the permutation sum of 20253 is $$02532+25320+53202+32025=113079$$Let $m$ and $n$ be two fivedigit integers with the same permutation sum.
Prove that $m=n$.
8 replies
Fermat_Fanatic108
Today at 1:41 PM
BR1F1SZ
an hour ago
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Tangent Spheres in a plane
ReticulatedPython   0
an hour ago
Three mutually tangent spheres with radius $6$ rest on a plane. A sphere with radius $8$ is tangent to all of them, but does not intersect nor lie on the plane. A sphere with radius $r$ lies on the plane, and is tangent to all three spheres with radius $6.$ Find the shortest distance between the sphere with radius $r$ and the sphere with radius $8.$

Source: Own
0 replies
ReticulatedPython
an hour ago
0 replies
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@@hard question
o.k.oo   0
2 hours ago
A total of 3300 handshakes were made at a party attended by 600 people. It was observed
that the total number of handshakes among any 300 people at the party is at least N. Find
the largest possible value for N.
0 replies
o.k.oo
2 hours ago
0 replies
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Max amount of equal numbers among (a_i^2 + a_j^2)/(a_i + a_j)
mshtand1   2
N 2 hours ago by mshtand1
Source: Ukrainian Mathematical Olympiad 2025. Day 2, Problem 9.8
Given $2025$ pairwise distinct positive integer numbers \(a_1, a_2, \ldots, a_{2025}\), find the maximum possible number of equal numbers among the fractions of the form
\[ \frac{a_i^2 + a_j^2}{a_i + a_j} \]
Proposed by Mykhailo Shtandenko
2 replies
mshtand1
Mar 14, 2025
mshtand1
2 hours ago
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Incenter geometry with parallel lines
nAalniaOMliO   2
N 2 hours ago by nAalniaOMliO
Source: Belarusian MO 2023
Let $\omega$ be the incircle of triangle $ABC$. Line $l_b$ is parallel to side $AC$ and tangent to $\omega$. Line $l_c$ is parallel to side $AB$ and tangent to $\omega$. It turned out that the intersection point of $l_b$ and $l_c$ lies on circumcircle of $ABC$
Find all possible values of $\frac{AB+AC}{BC}$
2 replies
nAalniaOMliO
Apr 16, 2024
nAalniaOMliO
2 hours ago
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Problem about Euler's function
luutrongphuc   3
N 3 hours ago by ishan.panpaliya
Prove that for every integer $n \ge 5$, we have:
$$ 2^{n^2+3n-13} \mid \phi \left(2^{2^{n}}-1 \right)$$
3 replies
luutrongphuc
Today at 4:23 PM
ishan.panpaliya
3 hours ago
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Function equation
Dynic   3
N 3 hours ago by Filipjack
Find all function $f:\mathbb{Z}\to\mathbb{Z}$ satisfy all conditions below:
i) $f(n+1)>f(n)$ for all $n\in \mathbb{Z}$
ii) $f(-n)=-f(n)$ for all $n\in \mathbb{Z}$
iii) $f(a^3+b^3+c^3+d^3)=f^3(a)+f^3(b)+f^3(c)+f^3(d)$ for all $n\in \mathbb{Z}$
3 replies
Dynic
Today at 5:10 PM
Filipjack
3 hours ago
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solve in positive integers: 3 \cdot 2^x +4 =n^2
parmenides51   3
N 4 hours ago by ali123456
Source: Greece JBMO TST 2019 p2
Find all pairs of positive integers $(x,n) $ that are solutions of the equation $3 \cdot 2^x +4 =n^2$.
3 replies
parmenides51
Apr 29, 2019
ali123456
4 hours ago
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J
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Geometry nationals problem
PenguFish   6
N Yesterday at 3:26 PM by PenguFish
I got Click to reveal hidden text and I just guessed and checked through most of it, also idek if I can post this (lol) but if i can, please help me!
6 replies
PenguFish
Mar 17, 2025
PenguFish
Yesterday at 3:26 PM
J
Geometry nationals problem
G H J
Reveal topic tags
geometry
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G H BBookmark kLocked kLocked NReply
The post below has been deleted. Click to close.
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PenguFish
17 posts
PenguFish
#1 h  Mar 17, 2025, 6:24 AM
Y by
I got Click to reveal hidden text and I just guessed and checked through most of it, also idek if I can post this (lol) but if i can, please help me!
Attachments:
This post has been edited 1 time. Last edited by PenguFish, Mar 17, 2025, 6:25 AM
Z K Y
The post below has been deleted. Click to close.
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PenguFish
17 posts
PenguFish
#3 h  Mar 17, 2025, 6:26 AM
Y by
For people who need more info on the volume, I got Click to reveal hidden text
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
ibmo0907
1195 posts
ibmo0907
#4 h  Mar 17, 2025, 7:11 AM
Y by
Non-rigorous sol
This post has been edited 3 times. Last edited by ibmo0907, Mar 17, 2025, 4:27 PM
Z K Y
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PenguFish
17 posts
PenguFish
#5 h  Mar 17, 2025, 4:25 PM • 1 Y
Y by ibmo0907
Ok thank you!
Z K Y
The post below has been deleted. Click to close.
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EaZ_Shadow
1107 posts
EaZ_Shadow
#6 h  Monday at 11:58 PM
Y by
There is a thread already
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
ibmo0907
1195 posts
ibmo0907
#7 h  Yesterday at 12:14 AM
Y by
EaZ_Shadow wrote:
There is a thread already
There's no proper sol on that thread
Z K Y
The post below has been deleted. Click to close.
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PenguFish
17 posts
PenguFish
#8 h  Yesterday at 3:26 PM
Y by
Oops, my bad for not looking for it
Z K Y
N Quick Reply
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