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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:
[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]
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0 replies
jlacosta
May 1, 2025
0 replies
Cyclic Quad. and Intersections
Thelink_20   11
N 5 minutes ago by americancheeseburger4281
Source: My Problem
Let $ABCD$ be a quadrilateral inscribed in a circle $\Gamma$. Let $AC\cap BD=E$, $AB\cap CD=F$, $(AEF)\cap\Gamma=X$, $(BEF)\cap\Gamma=Y$, $(CEF)\cap\Gamma=Z$, $(DEF)\cap\Gamma=W$, $XZ\cap YW=M$, $XY\cap ZW=N$. Prove that $MN$ lies over $EF$.
11 replies
Thelink_20
Oct 29, 2024
americancheeseburger4281
5 minutes ago
Serbian selection contest for the IMO 2025 - P6
OgnjenTesic   15
N 13 minutes ago by math90
Source: Serbian selection contest for the IMO 2025
For an $n \times n$ table filled with natural numbers, we say it is a divisor table if:
- the numbers in the $i$-th row are exactly all the divisors of some natural number $r_i$,
- the numbers in the $j$-th column are exactly all the divisors of some natural number $c_j$,
- $r_i \ne r_j$ for every $i \ne j$.

A prime number $p$ is given. Determine the smallest natural number $n$, divisible by $p$, such that there exists an $n \times n$ divisor table, or prove that such $n$ does not exist.

Proposed by Pavle Martinović
15 replies
OgnjenTesic
May 22, 2025
math90
13 minutes ago
Easy Number Theory
math_comb01   39
N 30 minutes ago by Adywastaken
Source: INMO 2024/3
Let $p$ be an odd prime and $a,b,c$ be integers so that the integers $$a^{2023}+b^{2023},\quad b^{2024}+c^{2024},\quad a^{2025}+c^{2025}$$are divisible by $p$.
Prove that $p$ divides each of $a,b,c$.
$\quad$
Proposed by Navilarekallu Tejaswi
39 replies
math_comb01
Jan 21, 2024
Adywastaken
30 minutes ago
Painting Beads on Necklace
amuthup   46
N 37 minutes ago by quantam13
Source: 2021 ISL C2
Let $n\ge 3$ be a fixed integer. There are $m\ge n+1$ beads on a circular necklace. You wish to paint the beads using $n$ colors, such that among any $n+1$ consecutive beads every color appears at least once. Find the largest value of $m$ for which this task is $\emph{not}$ possible.

Carl Schildkraut, USA
46 replies
amuthup
Jul 12, 2022
quantam13
37 minutes ago
Vieta's in arithmetic progression
elpianista227   1
N 4 hours ago by elpianista227
The roots of $x^3 - 30x^2 + cx - 120$ are in arithmetic progression. Find the value of $c$.
1 reply
elpianista227
4 hours ago
elpianista227
4 hours ago
16th Philippine Mathematical Olympiad (PMO) Area Stage Part II. #3
Siopao_Enjoyer   1
N 5 hours ago by Siopao_Enjoyer
If p is a real constant such that the roots of the equation x³ − 6px² + 5px + 88 = 0 form an arithmetic sequence, find p.
1 reply
Siopao_Enjoyer
5 hours ago
Siopao_Enjoyer
5 hours ago
Logarithms
P162008   1
N 5 hours ago by alexheinis
Let $a = \log_{3} 5, b = \log_{3} 4$ and $c = -\log_{3} 20.$
Evaluate $\sum_{cyc} \frac{a^2 + b^2}{a^2 + b^2 + ab}.$
1 reply
P162008
Yesterday at 1:40 PM
alexheinis
5 hours ago
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LilKirb   1
N 6 hours ago by LilKirb
Find the sum of all value(s) of $b$ such that
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\]
1 reply
LilKirb
6 hours ago
LilKirb
6 hours ago
27th Philippine Mathematical Olympiad Area Stage #5
Siopao_Enjoyer   1
N 6 hours ago by Siopao_Enjoyer
Find the sum of the cubes of the roots of the polynomial p(x)=x^3-x^2+2x-3.
1 reply
Siopao_Enjoyer
6 hours ago
Siopao_Enjoyer
6 hours ago
Help me please
dssdgeww   1
N 6 hours ago by whwlqkd
Prove that there exists a positive integer n with 2024 prime divisors such that n| 2^n + 1
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dssdgeww
Today at 3:20 AM
whwlqkd
6 hours ago
[PMO20 Qualifying I.13] Log raised to Log
LilKirb   1
N Today at 3:39 AM by LilKirb
Find the sum of the solutions to the logarithmic equation:
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LilKirb
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k my brain isn't working :(
missmaialee   39
N Today at 3:38 AM by sl1345961
Compute $(-1)^{11}-1^{10}+2^9+(-2)^8$.
39 replies
missmaialee
Yesterday at 9:45 PM
sl1345961
Today at 3:38 AM
Inequalitis
sqing   0
Today at 2:44 AM
Let $ a,b,c\geq  0 , a^2+b^2+c^2 =3.$ Prove that
$$a^3 +b^3 +c^3 +\frac{11}{5}abc  \leq \frac{26}{5}$$
0 replies
sqing
Today at 2:44 AM
0 replies
Algebraic Manipulation
Darealzolt   4
N Today at 2:22 AM by jasperE3
It is known that \(a,b \in \mathbb{R}\) that satisfies
\[
a^3+b^3=1957
\]\[
(a+b)(a+1)(b+1)=2014
\]Hence, find the value of \(a+b\)
4 replies
Darealzolt
Yesterday at 4:01 AM
jasperE3
Today at 2:22 AM
Sine inequality greater than twice triangle area
orl   3
N Aug 5, 2024 by parmenides51
Source: AIMO 2007, TST 5, P3
Let $ ABC$ be a triangle and $ P$ an arbitrary point in the plane. Let $ \alpha, \beta, \gamma$ be interior angles of the triangle and its area is denoted by $ F.$ Prove:
\[ \ov{AP}^2 \cdot \sin 2\alpha + \ov{BP}^2 \cdot \sin 2\beta + \ov{CP}^2 \cdot \sin 2\gamma \geq 2F
\]

When does equality occur?
3 replies
orl
Jan 11, 2009
parmenides51
Aug 5, 2024
Sine inequality greater than twice triangle area
G H J
Source: AIMO 2007, TST 5, P3
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orl
3647 posts
#1 • 2 Y
Y by Adventure10, Mango247
Let $ ABC$ be a triangle and $ P$ an arbitrary point in the plane. Let $ \alpha, \beta, \gamma$ be interior angles of the triangle and its area is denoted by $ F.$ Prove:
\[ \ov{AP}^2 \cdot \sin 2\alpha + \ov{BP}^2 \cdot \sin 2\beta + \ov{CP}^2 \cdot \sin 2\gamma \geq 2F
\]

When does equality occur?
Z K Y
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mkrnic
41 posts
#2 • 1 Y
Y by Adventure10
Dose anybody have the solution of this problem?
Obviouosly equality occurs if P is circumcenter..
Z K Y
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Michael Niland
681 posts
#3 • 1 Y
Y by Adventure10
Hint:Click to reveal hidden text
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parmenides51
30653 posts
#4
Y by
Let $ ABC$ be a triangle and $ P$ an arbitrary point in the plane. Let $ \alpha, \beta, \gamma$ be interior angles of the triangle and its area is denoted by $ F.$ Prove:
$$ AP^2 \cdot \sin 2\alpha + BP^2 \cdot \sin 2\beta + CP^2 \cdot \sin 2\gamma \geq 2F$$When does equality occur?

Click to reveal hidden text
This post has been edited 1 time. Last edited by parmenides51, Aug 6, 2024, 10:02 PM
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