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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
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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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IMO 2008, Question 1
orl   153
N 4 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
4 minutes ago
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P(x) doesn't have 2024 distinct real roots
gatnghiep   1
N 7 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
7 minutes ago
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A lies on the radical axis of BQX and CPX
a_507_bc   35
N 35 minutes ago by jordiejoh
Source: APMO 2024 P1
Let $ABC$ be an acute triangle. Let $D$ be a point on side $AB$ and $E$ be a point on side $AC$ such that lines $BC$ and $DE$ are parallel. Let $X$ be an interior point of $BCED$. Suppose rays $DX$ and $EX$ meet side $BC$ at points $P$ and $Q$, respectively, such that both $P$ and $Q$ lie between $B$ and $C$. Suppose that the circumcircles of triangles $BQX$ and $CPX$ intersect at a point $Y \neq X$. Prove that the points $A, X$, and $Y$ are collinear.
35 replies
a_507_bc
Jul 29, 2024
jordiejoh
35 minutes ago
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sum(ab/4a^2+b^2) <= 3/5
truongphatt2668   3
N an hour ago by Nguyenhuyen_AG
Source: I remember I read it somewhere
Let $a,b,c>0$. Prove that:
$$\dfrac{ab}{a^2+4b^2} + \dfrac{bc}{b^2+4c^2} + \dfrac{ca}{c^2+4a^2} \le \dfrac{3}{5}$$
3 replies
truongphatt2668
Monday at 1:23 PM
Nguyenhuyen_AG
an hour ago
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No more topics!
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r_0r_1... r_n/ R_0R_1...R_n independent of n or points, inradii exradii related
parmenides51   1
N Nov 13, 2021 by vanstraelen
Source: 1994 Estonia TST p1
Draw from the vertex $B$ of the triangle $ABC$ $n$ rays that intersect the side $AC$ at points $X_1, X_2,..., X_n$ respectively. (points $A, X_1,..., X_n, C$ lie on the line $AC$ in this order). Let $r_0, r_1,... , r_n$ and $R_0, R_1,... , R_n$ be the radii of the inscribed and exscribed circles triangles $ABX_1, X_1BX_2,..., X_nBC$ respectivley (see figure). Prove that the number $\frac{r_0r_1... r_n} {R_0R_1... R_n}$ does not depend on the number $n$ of rays or the selection of the points $X_1, X_2,..., X_n$ .
IMAGE
1 reply
parmenides51
Sep 22, 2020
vanstraelen
Nov 13, 2021
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r_0r_1... r_n/ R_0R_1...R_n independent of n or points, inradii exradii related
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Reveal topic tags
geometry
inradius
exradius
fixed
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Source: 1994 Estonia TST p1
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parmenides51
30629 posts
parmenides51
#1 h  Sep 22, 2020, 6:12 PM • 1 Y
Y by Lilathebee
Draw from the vertex $B$ of the triangle $ABC$ $n$ rays that intersect the side $AC$ at points $X_1, X_2,..., X_n$ respectively. (points $A, X_1,..., X_n, C$ lie on the line $AC$ in this order). Let $r_0, r_1,... , r_n$ and $R_0, R_1,... , R_n$ be the radii of the inscribed and exscribed circles triangles $ABX_1, X_1BX_2,..., X_nBC$ respectivley (see figure). Prove that the number $\frac{r_0r_1... r_n} {R_0R_1... R_n}$ does not depend on the number $n$ of rays or the selection of the points $X_1, X_2,..., X_n$ .
https://1.bp.blogspot.com/-fJBwc9wML8A/X2o-3yUIqgI/AAAAAAAAMh0/Q4qc0VZSrc8MYIziHu-2IFjQBbzraFvgACLcBGAsYHQ/s0/93%2Bestonia%2Btst.png
This post has been edited 2 times. Last edited by parmenides51, Sep 22, 2020, 6:14 PM
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vanstraelen
8945 posts
vanstraelen
#2 h  Nov 13, 2021, 7:26 PM • 1 Y
Y by Lilathebee
Let $AB=c,BC=a,CA=b$.

The number $\frac{r_0r_1 \cdots r_n} {R_0R_1 \cdots R_n}=\frac{a+c-b}{a+c+b}$.
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