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k a May Highlights and 2025 AoPS Online Class Information
jlacosta   0
Thursday at 11:16 PM
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
Thursday at 11:16 PM
0 replies
Aops is malware
Speedysolver1   14
N 17 minutes ago by Speedysolver1
See the image they are trying to track me
14 replies
Speedysolver1
Yesterday at 10:51 PM
Speedysolver1
17 minutes ago
Equivalent condition of the uniformly continuous fo a function
Alphaamss   0
4 hours ago
Source: Personal
Let $f_{a,b}(x)=x^a\cos(x^b),x\in(0,\infty)$. Get all the $(a,b)\in\mathbb R^2$ such that $f_{a,b}$ is uniformly continuous on $(0,\infty)$.
0 replies
Alphaamss
4 hours ago
0 replies
Find all continuous functions
bakkune   2
N 4 hours ago by bakkune
Source: Own
Find all continuous function $f, g\colon\mathbb{R}\to\mathbb{R}$ satisfied
$$
(x - k)f(x) = \int_k^x g(y)\mathrm{d}y 
$$for all $x\in\mathbb{R}$ and all $k\in\mathbb{Z}$.
2 replies
bakkune
6 hours ago
bakkune
4 hours ago
ISI 2019 : Problem #2
integrated_JRC   40
N 5 hours ago by Sammy27
Source: I.S.I. 2019
Let $f:(0,\infty)\to\mathbb{R}$ be defined by $$f(x)=\lim_{n\to\infty}\cos^n\bigg(\frac{1}{n^x}\bigg)$$(a) Show that $f$ has exactly one point of discontinuity.
(b) Evaluate $f$ at its point of discontinuity.
40 replies
integrated_JRC
May 5, 2019
Sammy27
5 hours ago
Cube Colouring Problems
Saucepan_man02   0
5 hours ago
Could anyone kindly post some problems (and hopefully along the solution thread/final answer) related to combinatorial colouring of cube?
0 replies
Saucepan_man02
5 hours ago
0 replies
Introducing myself at AoPS, and what's your magic wand?
asuth_asuth   1113
N 5 hours ago by Craftybutterfly
Hi!

I'm Andrew Sutherland. I'm the new Chief Product Officer at AoPS. As you may have read, Richard is retiring and Ben Kornell and I are working together to lead the company now. I'm leading all the software and digital stuff at AoPS. I just wanted to say hello and introduce myself! I'm really excited to be part of the special community that is AoPS.

Previously, I founded Quizlet as a 15-year-old high school student. I did Course 6 at MIT and then left to lead Quizlet full-time for a total of 14 years. I took a few years off and now I'm doing AoPS! I wrote more about all that on my blog: https://asuth.com/im-joining-aops

I have a question for all of you. If you could wave a magic wand, and change anything about AoPS, what would it be? All suggestions welcome! Thank you.
1113 replies
asuth_asuth
Mar 30, 2025
Craftybutterfly
5 hours ago
Putnam 1956 A4
sqrtX   2
N Today at 5:22 AM by sangsidhya
Source: Putnam 1956
Suppose that the $n$ times differentiable real function $f(x)$ has at least $n+1$ distinct zeros in the closed interval $[a,b]$ and that the polynomial $P(z)=z^n +c_{n-1}z^{n-1}+\ldots+c_1 x +c_0$ has only real zeroes. Show that
$f^{(n)}(x)+ c_{n-1} f^{(n-1)}(x) +\ldots +c_1 f'(x)+ c_0 f(x)$ has at least one zero in $[a,b]$, where $f^{(n)}$ denotes the $n$-th derivative of $f.$
2 replies
sqrtX
Jul 5, 2022
sangsidhya
Today at 5:22 AM
A problem in point set topology
tobylong   0
Today at 3:14 AM
Source: Basic Topology, Armstrong
Let $f:X\to Y$ be a closed map with the property that the inverse image of each point in $Y$ is a compact subset of $X$. Prove that $f^{-1}(K)$ is compact whenever $K$ is compact in $Y$.
0 replies
tobylong
Today at 3:14 AM
0 replies
Reply box disappearing
Craftybutterfly   16
N Yesterday at 10:15 PM by Craftybutterfly
For some reason, on my iPhone XR, when I press on the view my posts button, then press on an unlocked topic and scroll down or press go down button, the reply box disappears. I can’t use the proper format right now as I am on phone.
Summary of the problem: the lines above
setps to reproduce:
1. Go to your profile
2. Press on your posts button
3. press an unlocked topic and scroll down
Frequency: 100%
Browser: Chrome latest version
Device: iPhone XR
16 replies
Craftybutterfly
Apr 30, 2025
Craftybutterfly
Yesterday at 10:15 PM
Putnnam 1954 B2
sqrtX   3
N Yesterday at 9:13 PM by centslordm
Source: Putnam 1954
Let $s$ denote the sum of the alternating harmonic series. Rearrange this series as follows
$$1 + \frac{1}{3} - \frac{1}{2} + \frac{1}{5} +\frac{1}{7} - \frac{1}{4} + \frac{1}{9} + \frac{1}{11} - \ldots$$Assume as known that this series converges as well and denote its sum by $S$. Denote by $s_k, S_k$ respectively the $k$-th partial sums of both series. Prove that
$$ \!\!\!\! \text{i})\; S_{3n} = s_{4n} +\frac{1}{2} s_{2n}.$$$$ \text{ii}) \; S\ne s.$$
3 replies
sqrtX
Jul 17, 2022
centslordm
Yesterday at 9:13 PM
Putnam 1954 B1
sqrtX   5
N Yesterday at 8:56 PM by centslordm
Source: Putnam 1954
Show that the equation $x^2 -y^2 =a^3$ has always integral solutions for $x$ and $y$ whenever $a$ is a positive integer.
5 replies
sqrtX
Jul 17, 2022
centslordm
Yesterday at 8:56 PM
Putnam 1954 A6
sqrtX   1
N Yesterday at 8:52 PM by centslordm
Source: Putnam 1954
Suppose that $u_0 , u_1 ,\ldots$ is a sequence of real numbers such that
$$u_n =  \sum_{k=1}^{\infty} u_{n+k}^{2}\;\;\; \text{for} \; n=0,1,2,\ldots$$Prove that if $\sum u_n$ converges, then $u_k=0$ for all $k$.
1 reply
sqrtX
Jul 17, 2022
centslordm
Yesterday at 8:52 PM
Putnam 1954 A3
sqrtX   2
N Yesterday at 8:49 PM by centslordm
Source: Putnam 1954
Prove that if the family of integral curves of the differential equation
$$ \frac{dy}{dx} +p(x) y= q(x),$$where $p(x) q(x) \ne 0$, is cut by the line $x=k$ the tangents at the points of intersection are concurrent.
2 replies
sqrtX
Jul 17, 2022
centslordm
Yesterday at 8:49 PM
Cannot post PHP
char0221   4
N Yesterday at 1:02 PM by k1glaucus
Summary of the problem: If I try to post anything with PHP (a coding language), it
Page URL: In any forum or private messages
Steps to reproduce:
1. Create a post.
2. Put some PHP inside, can't give example
Expected behavior: Should post the message
Frequency: 100%
Operating system(s): macOS Sequoia 15.2.1
Browser(s), including version: Safari
Additional information: See attachments
4 replies
char0221
Apr 30, 2025
k1glaucus
Yesterday at 1:02 PM
k User number of posts status error
XAN4   5
N Feb 22, 2025 by bpan2021
Today I was browsing the forum High School Olympiads. There's a user whose username is the_universe6626, but then, when I flicked down to browse earlier answers today(note: I didn't 'search for this user's posts'), I found that one of them was labeled '23 posts'. I browsed his earlier answers today, and the number of posts increases, from 25 posts in the morning all the way to 36 posts right now. Is this a feature or a bug? If it is a feature, then certainly I haven't seen it elsewhere.
5 replies
XAN4
Feb 21, 2025
bpan2021
Feb 22, 2025
User number of posts status error
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XAN4
60 posts
#1
Y by
Today I was browsing the forum High School Olympiads. There's a user whose username is the_universe6626, but then, when I flicked down to browse earlier answers today(note: I didn't 'search for this user's posts'), I found that one of them was labeled '23 posts'. I browsed his earlier answers today, and the number of posts increases, from 25 posts in the morning all the way to 36 posts right now. Is this a feature or a bug? If it is a feature, then certainly I haven't seen it elsewhere.
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Demetri
1341 posts
#2
Y by
Today I was browsing the forum High School Olympiads. There's a user whose username is the_universe6626, but then, when I flicked down to browse earlier answers today(note: I didn't 'search for this user's posts'), I found that one of them was labeled '23 posts'. I browsed his earlier answers today, and the number of posts increases, from 25 posts in the morning all the way to 36 posts right now. Is this a feature or a bug? If it is a feature, then certainly I haven't seen it elsewhere.
Refresh maybe? I cannot reproduce.
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KangarooPrecise
1250 posts
#3
Y by
Maybe he/she posted a lot?
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bpan2021
2628 posts
#4 • 1 Y
Y by Demetri
It shouldn't be a feature. It may be because of the fact that they have posted 11 posts during the time you were looking through the threads.
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XAN4
60 posts
#5
Y by
bpan2021 wrote:
It shouldn't be a feature. It may be because of the fact that they have posted 11 posts during the time you were looking through the threads.
That shouldn't be true, because I logged in at 9 pm, and the earlier post at 7 am or something shows he/she posted 23, and the latest 36.
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bpan2021
2628 posts
#6
Y by
The post count of a user goes up whenever they post in specific forums. (Other forums do not count towards post count, but this idea is besides the point.)

It's possible that: your cache from a previous session carried over, and the post number from that user didn't refresh when you first viewed this user's post number, and it refreshed when you viewed the post count the second time.

Or, the user you were looking at posted between the first time you viewed their post count and the second time you viewed their post count, so their post count updated.

If the issue you're having isn't the one I'm explaining, please clarify.
This post has been edited 3 times. Last edited by bpan2021, Feb 22, 2025, 2:42 AM
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