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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:
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[*]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]
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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
J
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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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help me~~
Imshyso   0
24 minutes ago
Given triangle ABC inscribed in (O) with orthocenter H. Let K be the midpoint of AH. Take E,F on AC, AB so that BKE=CKF=90. Prove that E,O,F are collinear.
0 replies
+1 w
Imshyso
24 minutes ago
0 replies
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Basic ideas in junior diophantine equations
Maths_VC   5
N 38 minutes ago by Royal_mhyasd
Source: Serbia JBMO TST 2025, Problem 3
Determine all positive integers $a, b$ and $c$ such that
$2$ $\cdot$ $10^a + 5^b = 2025^c$
5 replies
Maths_VC
May 27, 2025
Royal_mhyasd
38 minutes ago
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Find values for a, b ,c
Ferum_2710   2
N 39 minutes ago by Jupiterballs
Source: Romania JBMO tst 2023 day2 p4
Let $M \geq 1$ be a real number. Determine all natural numbers $n$ for which there exist distinct natural numbers $a$, $b$, $c > M$, such that
$n = (a,b) \cdot (b,c) + (b,c) \cdot (c,a) + (c,a) \cdot (a,b)$
(where $(x,y)$ denotes the greatest common divisor of natural numbers $x$ and $y$).
2 replies
Ferum_2710
Apr 30, 2023
Jupiterballs
39 minutes ago
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Center lies on circumcircle of other
Philomath_314   41
N an hour ago by Adywastaken
Source: INMO P1
In triangle $ABC$ with $CA=CB$, point $E$ lies on the circumcircle of $ABC$ such that $\angle ECB=90^{\circ}$. The line through $E$ parallel to $CB$ intersects $CA$ in $F$ and $AB$ in $G$. Prove that the center of the circumcircle of triangle $EGB$ lies on the circumcircle of triangle $ECF$.

Proposed by Prithwijit De
41 replies
Philomath_314
Jan 21, 2024
Adywastaken
an hour ago
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find question
mathematical-forest   7
N an hour ago by whwlqkd
Are there any contest questions that seem simple but are actually difficult? :-D
7 replies
mathematical-forest
Thursday at 10:19 AM
whwlqkd
an hour ago
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Inspired by a cool result
DoThinh2001   1
N an hour ago by arqady
Source: Old?
Let three real numbers $a,b,c\geq 0$, no two of which are $0$. Prove that:
$$\sqrt{\frac{a^2+bc}{b^2+c^2}}+\sqrt{\frac{b^2+ca}{c^2+a^2}}+\sqrt{\frac{c^2+ab}{a^2+b^2}}\geq 2+\sqrt{\frac{ab+bc+ca}{a^2+b^2+c^2}}.$$
Inspiration
1 reply
+1 w
DoThinh2001
Today at 12:08 AM
arqady
an hour ago
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Crossing ٍٍChords
matinyousefi   1
N 2 hours ago by Trenod
Source: Iranian Combinatorics Olympiad 2020 P3
$1399$ points and some chords between them is given.
$a)$ In every step we can take two chords $RS,PQ$ with a common point other than $P,Q,R,S$ and erase exactly one of $RS,PQ$ and draw $PS,PR,QS,QR$ let $s$ be the minimum of chords after some steps. Find the maximum of $s$ over all initial positions.
$b)$ In every step we can take two chords $RS,PQ$ with a common point other than $P,Q,R,S$ and erase both of $RS,PQ$ and draw $PS,PR,QS,QR$ let $s$ be the minimum of chords after some steps. Find the maximum of $s$ over all initial positions.

Proposed by Afrouz Jabalameli, Abolfazl Asadi
1 reply
matinyousefi
Apr 24, 2020
Trenod
2 hours ago
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Nice NT with powers of two
oVlad   7
N 2 hours ago by SimplisticFormulas
Source: Romania TST 2024 Day 1 P3
Let $n{}$ be a positive integer and let $a{}$ and $b{}$ be positive integers congruent to 1 modulo 4. Prove that there exists a positive integer $k{}$ such that at least one of the numbers $a^k-b$ and $b^k-a$ is divisible by $2^n.$

Cătălin Liviu Gherghe
7 replies
oVlad
Jul 31, 2024
SimplisticFormulas
2 hours ago
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D,E,F are collinear.
TUAN2k8   2
N 2 hours ago by TUAN2k8
Source: Own
Help me with this:
2 replies
TUAN2k8
May 28, 2025
TUAN2k8
2 hours ago
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Combinatorial identity
MehdiGolafshan   4
N 2 hours ago by watery
Let $n$ is a positive integer. Prove that
$$\sum_{k=0}^{n-1}\frac{1}{k+1}\binom{n-1}{k} = \frac{2^n-1}{n}.$$
4 replies
MehdiGolafshan
Jan 16, 2023
watery
2 hours ago
J
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Overly wordy problems
ZMB038   11
N 3 hours ago by Yiyj
Hey everyone, here we can post questions with way to many extraneous words, that are actually easy.
Try to solve the one above yours.
I'll start:
Click to reveal hidden text
11 replies
ZMB038
May 28, 2025
Yiyj
3 hours ago
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Worst Sillies of All Time
pingpongmerrily   40
N 3 hours ago by Yiyj
Share the worst sillies you have ever made!

Mine was probably on the 2024 MathCounts State Target Round Problem 8, where I wrote my answer as a fraction instead of a percent, which cost me a trip to Nationals that year.
40 replies
pingpongmerrily
Yesterday at 12:34 PM
Yiyj
3 hours ago
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MathDash help
Spacepandamath13   6
N 5 hours ago by elizhang101412
AkshajK ORZ by the way invited me to do MathDash a few months ago and I did try it one day but haven't done it much after (Sorry). Now, I'm getting back into it and finding the format kind of weird. When selecting certain problem type sometimes it lets me pick immediately, other times not. Any fixes?
6 replies
Spacepandamath13
Thursday at 9:32 PM
elizhang101412
5 hours ago
J
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Combi counting
Caasi_Gnow   2
N 5 hours ago by Justbrick
Find the number of different ways to arrange seven people around a circular meeting table if A and B must sit together and C and D cannot sit next to each other. (Note: the order for A and B might be A,B or B,A)
2 replies
Caasi_Gnow
Mar 20, 2025
Justbrick
5 hours ago
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Geometry
BQK   15
N Apr 26, 2025 by b2025tyx
Help me, Why geometry is so difficult to learn
15 replies
BQK
Apr 24, 2025
b2025tyx
Apr 26, 2025
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Geometry
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Reveal topic tags
geometry
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BQK
1 post
BQK
#1 h  Apr 24, 2025, 2:58 PM • 1 Y
Y by PikaPika999
Help me, Why geometry is so difficult to learn
Z K Y
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MathWinner121
533 posts
MathWinner121
#5 h  Apr 24, 2025, 3:56 PM • 2 Y
Y by EthanNg6, PikaPika999
BQK wrote:
Help me, Why geometry is so difficult to learn

Focus on understanding the material instead of memorizing the material.
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anticodon
201 posts
anticodon
#6 h  Apr 24, 2025, 5:07 PM • 2 Y
Y by sangriabeaver5, PikaPika999
draw a good diagram
(don't be that one person who draws an 110 degree angle that looks more like 40 degrees)
Z K Y
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bluedino24
161 posts
bluedino24
#9 h  Apr 25, 2025, 1:25 PM
Y by
BQK wrote:
Help me, Why geometry is so difficult to learn
It's good to keep focus on what you are trying to find. Many geometry problems are disguised as something complicated and messy, but are really simple as soon as you spot the right thing. Practice in general will help you get better at doing this. :)
This post has been edited 1 time. Last edited by bluedino24, Apr 25, 2025, 1:26 PM
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jb2015007
1973 posts
jb2015007
#14 h  Apr 25, 2025, 3:33 PM
Y by
js do p sets on amc trivial:https://amctrivial.com/?problems=2013_AMC_12A_Problems/Problem_11|2019_AMC_10A_Problems/Problem_19|2015_AIME_II_Problems/Problem_2|2010_AIME_I_Problems/Problem_8|2023_USAJMO_Problems/Problem_1
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Andrew2019
2328 posts
Andrew2019
#18 h  Apr 25, 2025, 4:25 PM
Y by
practice geo sets on mathdash
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sweetmailbox
51 posts
sweetmailbox
#29 h  Apr 25, 2025, 8:25 PM
Y by
@bluedino24 I respect the amount of patience you have, and I aspire to apply that when I do math.
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bluedino24
161 posts
bluedino24
#30 h  Apr 25, 2025, 8:27 PM
Y by
REDACTED
This post has been edited 2 times. Last edited by bluedino24, May 24, 2025, 2:42 AM
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bluedino24
161 posts
bluedino24
#33 h  Apr 25, 2025, 8:29 PM
Y by
REDACTED
This post has been edited 4 times. Last edited by bluedino24, May 24, 2025, 2:42 AM
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sadas123
1330 posts
sadas123
#35 h  Apr 26, 2025, 1:15 AM • 1 Y
Y by RollingPanda4616
I would say that for Geo, I just did all of the Alcumus Geo for it and then I practiced by doing past AMC 8 Final 5 Geo, then I started to do first 15 AMC 10 Geo, then Idk know what's next, maybe just try to do Olympiad Geo after this like euclidian Geo I am not sure
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valisaxieamc
506 posts
valisaxieamc
#36 h  Apr 26, 2025, 4:07 AM
Y by
K3mchi_ wrote:
bluedino24 wrote:
Maybe it's a good time to stop. The best people know when's the right time and when it's not.

Also, maybe it's time for you to enroll in an LA class...? You seem to be struggling with understanding the point I am trying to get across...

you fail to understand my antics and motives

You mean wasting other people's time? All the people in here, go here to learn or have fun not to hear your stupid comments on forums that serve no purpose. Can you not bring others down so you can feel better about yourself. Also you are in no position to talk, the most math you have done is amc 8 and you yourself said you sold on it. Why are you trying to talk down people who are better then you
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Evanlovemath
130 posts
Evanlovemath
#37 h  Apr 26, 2025, 4:13 AM • 1 Y
Y by mithu542
Why are you guys even arguing about this, someone just wanted help in geometry. Bruh.
This post has been edited 1 time. Last edited by Evanlovemath, Apr 26, 2025, 4:13 AM
Reason: b
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Evanlovemath
130 posts
Evanlovemath
#38 h  Apr 26, 2025, 4:14 AM • 1 Y
Y by mithu542
please stop arguing :)
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bluedino24
161 posts
bluedino24
#41 h  Apr 26, 2025, 2:51 PM
Y by
REDACTED
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b2025tyx
1483 posts
b2025tyx
#42 h  Apr 26, 2025, 2:53 PM
Y by
This guy just joined less than 24 hours ago
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b2025tyx
1483 posts
b2025tyx
#44 h  Apr 26, 2025, 3:04 PM
Y by
A response :

BQK joined yesterday at 11:26 am.

BQK is that guy

Johnny is alive

Johnny has a tuff jacket
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