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k a My Retirement & New Leadership at AoPS
rrusczyk   1571
N Mar 26, 2025 by SmartGroot
I write today to announce my retirement as CEO from Art of Problem Solving. When I founded AoPS 22 years ago, I never imagined that we would reach so many students and families, or that we would find so many channels through which we discover, inspire, and train the great problem solvers of the next generation. I am very proud of all we have accomplished and I’m thankful for the many supporters who provided inspiration and encouragement along the way. I'm particularly grateful to all of the wonderful members of the AoPS Community!

I’m delighted to introduce our new leaders - Ben Kornell and Andrew Sutherland. Ben has extensive experience in education and edtech prior to joining AoPS as my successor as CEO, including starting like I did as a classroom teacher. He has a deep understanding of the value of our work because he’s an AoPS parent! Meanwhile, Andrew and I have common roots as founders of education companies; he launched Quizlet at age 15! His journey from founder to MIT to technology and product leader as our Chief Product Officer traces a pathway many of our students will follow in the years to come.

Thank you again for your support for Art of Problem Solving and we look forward to working with millions more wonderful problem solvers in the years to come.

And special thanks to all of the amazing AoPS team members who have helped build AoPS. We’ve come a long way from here:IMAGE
1571 replies
rrusczyk
Mar 24, 2025
SmartGroot
Mar 26, 2025
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]
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
Mar 2, 2025
0 replies
2023 factors and perfect cube
proxima1681   6
N 6 minutes ago by L13832
Source: Indian Statistical Institute (ISI) UGB 2023 P4
Let $n_1, n_2, \cdots , n_{51}$ be distinct natural numbers each of which has exactly $2023$ positive integer factors. For instance, $2^{2022}$ has exactly $2023$ positive integer factors $1,2, 2^{2}, 2^{3}, \cdots 2^{2021}, 2^{2022}$. Assume that no prime larger than $11$ divides any of the $n_{i}$'s. Show that there must be some perfect cube among the $n_{i}$'s.
6 replies
proxima1681
May 14, 2023
L13832
6 minutes ago
Integer Symmetric Polynomials
proxima1681   4
N 36 minutes ago by mqoi_KOLA
Source: Indian Statistical Institute (ISI) UGB 2023 P7
(a) Let $n \geq 1$ be an integer. Prove that $X^n+Y^n+Z^n$ can be written as a polynomial with integer coefficients in the variables $\alpha=X+Y+Z$, $\beta= XY+YZ+ZX$ and $\gamma = XYZ$.
(b) Let $G_n=x^n \sin(nA)+y^n \sin(nB)+z^n \sin(nC)$, where $x,y,z, A,B,C$ are real numbers such that $A+B+C$ is an integral multiple of $\pi$. Using (a) or otherwise show that if $G_1=G_2=0$, then $G_n=0$ for all positive integers $n$.
4 replies
proxima1681
May 14, 2023
mqoi_KOLA
36 minutes ago
IMO 2008, Question 1
orl   153
N 41 minutes ago by QueenArwen
Source: IMO Shortlist 2008, G1
Let $ H$ be the orthocenter of an acute-angled triangle $ ABC$. The circle $ \Gamma_{A}$ centered at the midpoint of $ BC$ and passing through $ H$ intersects the sideline $ BC$ at points $ A_{1}$ and $ A_{2}$. Similarly, define the points $ B_{1}$, $ B_{2}$, $ C_{1}$ and $ C_{2}$.

Prove that the six points $ A_{1}$, $ A_{2}$, $ B_{1}$, $ B_{2}$, $ C_{1}$ and $ C_{2}$ are concyclic.

Author: Andrey Gavrilyuk, Russia
153 replies
orl
Jul 16, 2008
QueenArwen
41 minutes ago
P(x) doesn't have 2024 distinct real roots
gatnghiep   1
N 44 minutes ago by kiyoras_2001
Given a polynomial $P(x)=x^{2024}+a_{2023}x^{2023}+...+a_1x+1$ with real coefficient. It is known that $|a_{1012}|<2$ and $a_k = a_{2024-k}, \forall k = 1,2,...,2012$. Prove that $P(x)$ can't have $2024$ distinct real roots.
1 reply
gatnghiep
Oct 2, 2024
kiyoras_2001
44 minutes ago
Geo Mock #4
Bluesoul   1
N 3 hours ago by Sedro
Consider acute triangle $ABC$ with orthocenter $H$. Extend $AH$ to meet $BC$ at $D$. The angle bisector of $\angle{ABH}$ meets the midpoint of $AD$. If $AB=10, BH=6$, compute the area of $\triangle{ABC}$.
1 reply
Bluesoul
Yesterday at 7:03 AM
Sedro
3 hours ago
An inequality
JK1603JK   2
N 4 hours ago by lbh_qys
Let a,b,c\ge 0: a+b+c=3 then prove \frac{1}{a+1}+\frac{1}{b+1}+\frac{1}{c+1}\le \frac{27}{2}\cdot\frac{1}{2ab+2bc+2ca+3}.
2 replies
JK1603JK
5 hours ago
lbh_qys
4 hours ago
Geo Mock #3
Bluesoul   2
N Yesterday at 11:31 PM by mathprodigy2011
Consider square $ABCD$ with side length of $5$. The point $P$ is selected on the diagonal $AC$ such that $\angle{BPD}=135^{\circ}$. Denote the circumcenters of $\triangle{BPA}, \triangle{APD}$ as $O_1,O_2$. Find the length of $O_1O_2$
2 replies
Bluesoul
Yesterday at 7:02 AM
mathprodigy2011
Yesterday at 11:31 PM
Complex + Radical Evaluation
Saucepan_man02   3
N Yesterday at 4:45 PM by SmartHusky
Evaluate: (without calculators)
$$ (\sqrt{6 - 2 \sqrt{5}} + i \sqrt{2 \sqrt{5} + 10})^5 + (\sqrt{6 - 2 \sqrt{5}} - i \sqrt{2 \sqrt{5} + 10})^5$$
3 replies
Saucepan_man02
Mar 17, 2025
SmartHusky
Yesterday at 4:45 PM
Geo Mock #2
Bluesoul   1
N Yesterday at 4:36 PM by Sedro
Consider convex quadrilateral $ABCD$ such that $AB=6, BC=10, \angle{ABC}=90^{\circ}$. Denote the midpoints of $AD,CD$ as $M,N$ respectively, compute the area of $\triangle{BMN}$ given the area of $ABCD$ is $50$.
1 reply
Bluesoul
Yesterday at 6:59 AM
Sedro
Yesterday at 4:36 PM
Geo Mock #1
Bluesoul   1
N Yesterday at 4:30 PM by Sedro
Consider the rectangle $ABCD$ with $AB=4$. Point $E$ lies inside the rectangle such that $\triangle{ABE}$ is equilateral. Given that $C,E$ and the midpoint of $AD$ are on the same line, compute the length of $BC$.
1 reply
Bluesoul
Yesterday at 6:58 AM
Sedro
Yesterday at 4:30 PM
Inequalities (Please help me!!!)
yt12   6
N Yesterday at 4:16 PM by lamhihi1234
Let $a,b,c$ be reals with $a+b+c=1$and $ a,b,c \ge \frac{-3}{ 4}$. Prove that
$$\frac{a}{a^2+1}+\frac{b}{b^2+1}+\frac{c}{ c^2+1} \le \frac{9}{ 10}$$
6 replies
yt12
Mar 4, 2023
lamhihi1234
Yesterday at 4:16 PM
Inequalites 1/4
nhathhuyyp5c   1
N Yesterday at 12:27 PM by sqing
Let $a,b,c,d$ be non-negative reals such that $a+b+c+d=3$. Prove that $$a+ab+abc+abcd\leq 4$$
1 reply
nhathhuyyp5c
Yesterday at 6:10 AM
sqing
Yesterday at 12:27 PM
combionatrics question
Tony_stark0094   0
Yesterday at 12:08 PM
There are $2n$ people seated around a circular table, and $m$ cookies
are distributed among them. The cookies can be passed under the
following rules:
(a) Each person can only pass cookies to his or her neighbors
(b) Each time someone passes a cookie, he or she must also eat a
cookie
Let $A$ be one of these people. Find the least $m$ such that no matter
how $m$ cookies are distributed initially, there is a strategy to pass
cookies so that $A$ receives at least one cookie.
0 replies
Tony_stark0094
Yesterday at 12:08 PM
0 replies
Functional Equation
ab_xy123   4
N Yesterday at 10:35 AM by millennium2k
Find all solutions to the functional equation $f(1-x) = f(x) + 1 - 2x$
4 replies
ab_xy123
Mar 16, 2020
millennium2k
Yesterday at 10:35 AM
locus of intersections of non parallels isosceles trapezoids
parmenides51   1
N Jul 3, 2024 by old_csk_mo
Source: Czech And Slovak Mathematical Olympiad, Round III, A 2010 p4
A circle $k$ is given with a non-diameter chord $AC$. On the tangent at point $A$ select point $X \ne A$ and mark $D$ the intersection of the circle $k$ with the interior of the line $XC$ (if any). Let $B$ a point in circle $k$ such that quadrilateral $ABCD$ is a trapezoid . Determine the set of intersections of lines $BC$ and $AD$ belonging to all such trapezoids.
1 reply
parmenides51
Jan 31, 2020
old_csk_mo
Jul 3, 2024
locus of intersections of non parallels isosceles trapezoids
G H J
G H BBookmark kLocked kLocked NReply
Source: Czech And Slovak Mathematical Olympiad, Round III, A 2010 p4
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parmenides51
30629 posts
#1 • 1 Y
Y by Adventure10
A circle $k$ is given with a non-diameter chord $AC$. On the tangent at point $A$ select point $X \ne A$ and mark $D$ the intersection of the circle $k$ with the interior of the line $XC$ (if any). Let $B$ a point in circle $k$ such that quadrilateral $ABCD$ is a trapezoid . Determine the set of intersections of lines $BC$ and $AD$ belonging to all such trapezoids.
This post has been edited 1 time. Last edited by parmenides51, Jan 31, 2020, 11:24 AM
Z K Y
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old_csk_mo
102 posts
#2
Y by
official solution: https://www.matematickaolympiada.cz/media/3459589/a59angl.pdf#page=17
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N Quick Reply
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