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k a April Highlights and 2025 AoPS Online Class Information
jlacosta 0
Apr 2, 2025
Spring is in full swing and summer is right around the corner, what are your plans? At AoPS Online our schedule has new classes starting now through July, so be sure to keep your skills sharp and be prepared for the Fall school year! Check out the schedule of upcoming classes below.
WOOT early bird pricing is in effect, don’t miss out! If you took MathWOOT Level 2 last year, no worries, it is all new problems this year! Our Worldwide Online Olympiad Training program is for high school level competitors. AoPS designed these courses to help our top students get the deep focus they need to succeed in their specific competition goals. Check out the details at this link for all our WOOT programs in math, computer science, chemistry, and physics.
Looking for summer camps in math and language arts? Be sure to check out the video-based summer camps offered at the Virtual Campus that are 2- to 4-weeks in duration. 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 events:
[list][*]April 3rd (Webinar), 4pm PT/7:00pm ET, Learning with AoPS: Perspectives from a Parent, Math Camp Instructor, and University Professor
[*]April 8th (Math Jam), 4:30pm PT/7:30pm ET, 2025 MATHCOUNTS State Discussion
April 9th (Webinar), 4:00pm PT/7:00pm ET, Learn about Video-based Summer Camps at the Virtual Campus
[*]April 10th (Math Jam), 4:30pm PT/7:30pm ET, 2025 MathILy and MathILy-Er Math Jam: Multibackwards Numbers
[*]April 22nd (Webinar), 4:00pm PT/7:00pm ET, Competitive Programming at AoPS (USACO).[/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.
Introductory: Grades 5-10
Prealgebra 1 Self-Paced
Prealgebra 1
Sunday, Apr 13 - Aug 10
Tuesday, May 13 - Aug 26
Thursday, May 29 - Sep 11
Sunday, Jun 15 - Oct 12
Monday, Jun 30 - Oct 20
Wednesday, Jul 16 - Oct 29
Prealgebra 2 Self-Paced
Prealgebra 2
Sunday, Apr 13 - Aug 10
Wednesday, May 7 - Aug 20
Monday, Jun 2 - Sep 22
Sunday, Jun 29 - Oct 26
Friday, Jul 25 - Nov 21
Introduction to Algebra A Self-Paced
Introduction to Algebra A
Monday, Apr 7 - Jul 28
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Wednesday, May 14 - Aug 27
Friday, May 30 - Sep 26
Monday, Jun 2 - Sep 22
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Thursday, Jun 26 - Oct 9
Tuesday, Jul 15 - Oct 28
Introduction to Counting & Probability Self-Paced
Introduction to Counting & Probability
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Thursday, May 15 - Jul 31
Sunday, Jun 1 - Aug 24
Thursday, Jun 12 - Aug 28
Wednesday, Jul 9 - Sep 24
Sunday, Jul 27 - Oct 19
Introduction to Number Theory
Thursday, Apr 17 - Jul 3
Friday, May 9 - Aug 1
Wednesday, May 21 - Aug 6
Monday, Jun 9 - Aug 25
Sunday, Jun 15 - Sep 14
Tuesday, Jul 15 - Sep 30
Introduction to Algebra B Self-Paced
Introduction to Algebra B
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Wednesday, Jun 4 - Sep 17
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Friday, Jul 18 - Nov 14
Introduction to Geometry
Wednesday, Apr 23 - Oct 1
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Monday, Jun 16 - Dec 8
Friday, Jun 20 - Jan 9
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Intermediate: Grades 8-12
Intermediate Algebra
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Wednesday, Jun 25 - Dec 10
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Thursday, Jul 24 - Jan 22
Intermediate Counting & Probability
Wednesday, May 21 - Sep 17
Sunday, Jun 22 - Nov 2
Intermediate Number Theory
Friday, Apr 11 - Jun 27
Sunday, Jun 1 - Aug 24
Wednesday, Jun 18 - Sep 3
Precalculus
Wednesday, Apr 9 - Sep 3
Friday, May 16 - Oct 24
Sunday, Jun 1 - Nov 9
Monday, Jun 30 - Dec 8
Advanced: Grades 9-12
Olympiad Geometry
Tuesday, Jun 10 - Aug 26
Calculus
Tuesday, May 27 - Nov 11
Wednesday, Jun 25 - Dec 17
Group Theory
Thursday, Jun 12 - Sep 11
Contest Preparation: Grades 6-12
MATHCOUNTS/AMC 8 Basics
Wednesday, Apr 16 - Jul 2
Friday, May 23 - Aug 15
Monday, Jun 2 - Aug 18
Thursday, Jun 12 - Aug 28
Sunday, Jun 22 - Sep 21
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)
MATHCOUNTS/AMC 8 Advanced
Friday, Apr 11 - Jun 27
Sunday, May 11 - Aug 10
Tuesday, May 27 - Aug 12
Wednesday, Jun 11 - Aug 27
Sunday, Jun 22 - Sep 21
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)
AMC 10 Problem Series
Friday, May 9 - Aug 1
Sunday, Jun 1 - Aug 24
Thursday, Jun 12 - Aug 28
Tuesday, Jun 17 - Sep 2
Sunday, Jun 22 - Sep 21 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Monday, Jun 23 - Sep 15
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)
AMC 10 Final Fives
Sunday, May 11 - Jun 8
Tuesday, May 27 - Jun 17
Monday, Jun 30 - Jul 21
AMC 12 Problem Series
Tuesday, May 27 - Aug 12
Thursday, Jun 12 - Aug 28
Sunday, Jun 22 - Sep 21
Wednesday, Aug 6 - Oct 22
AMC 12 Final Fives
Sunday, May 18 - Jun 15
F=ma Problem Series
Wednesday, Jun 11 - Aug 27
WOOT Programs
Visit the pages linked for full schedule details for each of these programs!
MathWOOT Level 1
MathWOOT Level 2
ChemWOOT
CodeWOOT
PhysicsWOOT
Programming
Introduction to Programming with Python
Thursday, May 22 - Aug 7
Sunday, Jun 15 - Sep 14 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Tuesday, Jun 17 - Sep 2
Monday, Jun 30 - Sep 22
Intermediate Programming with Python
Sunday, Jun 1 - Aug 24
Monday, Jun 30 - Sep 22
USACO Bronze Problem Series
Tuesday, May 13 - Jul 29
Sunday, Jun 22 - Sep 1
Physics
Introduction to Physics
Wednesday, May 21 - Aug 6
Sunday, Jun 15 - Sep 14
Monday, Jun 23 - Sep 15
Physics 1: Mechanics
Thursday, May 22 - Oct 30
Monday, Jun 23 - Dec 15
Relativity
Sat & Sun, Apr 26 - Apr 27 (4:00 - 7:00 pm ET/1:00 - 4:00pm PT)
Mon, Tue, Wed & Thurs, Jun 23 - Jun 26 (meets every day of the week!)
WOOT early bird pricing is in effect, don’t miss out! If you took MathWOOT Level 2 last year, no worries, it is all new problems this year! Our Worldwide Online Olympiad Training program is for high school level competitors. AoPS designed these courses to help our top students get the deep focus they need to succeed in their specific competition goals. Check out the details at this link for all our WOOT programs in math, computer science, chemistry, and physics.
Looking for summer camps in math and language arts? Be sure to check out the video-based summer camps offered at the Virtual Campus that are 2- to 4-weeks in duration. 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 events:
[list][*]April 3rd (Webinar), 4pm PT/7:00pm ET, Learning with AoPS: Perspectives from a Parent, Math Camp Instructor, and University Professor
[*]April 8th (Math Jam), 4:30pm PT/7:30pm ET, 2025 MATHCOUNTS State Discussion
April 9th (Webinar), 4:00pm PT/7:00pm ET, Learn about Video-based Summer Camps at the Virtual Campus
[*]April 10th (Math Jam), 4:30pm PT/7:30pm ET, 2025 MathILy and MathILy-Er Math Jam: Multibackwards Numbers
[*]April 22nd (Webinar), 4:00pm PT/7:00pm ET, Competitive Programming at AoPS (USACO).[/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.
Introductory: Grades 5-10
Prealgebra 1 Self-Paced
Prealgebra 1
Sunday, Apr 13 - Aug 10
Tuesday, May 13 - Aug 26
Thursday, May 29 - Sep 11
Sunday, Jun 15 - Oct 12
Monday, Jun 30 - Oct 20
Wednesday, Jul 16 - Oct 29
Prealgebra 2 Self-Paced
Prealgebra 2
Sunday, Apr 13 - Aug 10
Wednesday, May 7 - Aug 20
Monday, Jun 2 - Sep 22
Sunday, Jun 29 - Oct 26
Friday, Jul 25 - Nov 21
Introduction to Algebra A Self-Paced
Introduction to Algebra A
Monday, Apr 7 - Jul 28
Sunday, May 11 - Sep 14 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Wednesday, May 14 - Aug 27
Friday, May 30 - Sep 26
Monday, Jun 2 - Sep 22
Sunday, Jun 15 - Oct 12
Thursday, Jun 26 - Oct 9
Tuesday, Jul 15 - Oct 28
Introduction to Counting & Probability Self-Paced
Introduction to Counting & Probability
Wednesday, Apr 16 - Jul 2
Thursday, May 15 - Jul 31
Sunday, Jun 1 - Aug 24
Thursday, Jun 12 - Aug 28
Wednesday, Jul 9 - Sep 24
Sunday, Jul 27 - Oct 19
Introduction to Number Theory
Thursday, Apr 17 - Jul 3
Friday, May 9 - Aug 1
Wednesday, May 21 - Aug 6
Monday, Jun 9 - Aug 25
Sunday, Jun 15 - Sep 14
Tuesday, Jul 15 - Sep 30
Introduction to Algebra B Self-Paced
Introduction to Algebra B
Wednesday, Apr 16 - Jul 30
Tuesday, May 6 - Aug 19
Wednesday, Jun 4 - Sep 17
Sunday, Jun 22 - Oct 19
Friday, Jul 18 - Nov 14
Introduction to Geometry
Wednesday, Apr 23 - Oct 1
Sunday, May 11 - Nov 9
Tuesday, May 20 - Oct 28
Monday, Jun 16 - Dec 8
Friday, Jun 20 - Jan 9
Sunday, Jun 29 - Jan 11
Monday, Jul 14 - Jan 19
Intermediate: Grades 8-12
Intermediate Algebra
Monday, Apr 21 - Oct 13
Sunday, Jun 1 - Nov 23
Tuesday, Jun 10 - Nov 18
Wednesday, Jun 25 - Dec 10
Sunday, Jul 13 - Jan 18
Thursday, Jul 24 - Jan 22
Intermediate Counting & Probability
Wednesday, May 21 - Sep 17
Sunday, Jun 22 - Nov 2
Intermediate Number Theory
Friday, Apr 11 - Jun 27
Sunday, Jun 1 - Aug 24
Wednesday, Jun 18 - Sep 3
Precalculus
Wednesday, Apr 9 - Sep 3
Friday, May 16 - Oct 24
Sunday, Jun 1 - Nov 9
Monday, Jun 30 - Dec 8
Advanced: Grades 9-12
Olympiad Geometry
Tuesday, Jun 10 - Aug 26
Calculus
Tuesday, May 27 - Nov 11
Wednesday, Jun 25 - Dec 17
Group Theory
Thursday, Jun 12 - Sep 11
Contest Preparation: Grades 6-12
MATHCOUNTS/AMC 8 Basics
Wednesday, Apr 16 - Jul 2
Friday, May 23 - Aug 15
Monday, Jun 2 - Aug 18
Thursday, Jun 12 - Aug 28
Sunday, Jun 22 - Sep 21
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)
MATHCOUNTS/AMC 8 Advanced
Friday, Apr 11 - Jun 27
Sunday, May 11 - Aug 10
Tuesday, May 27 - Aug 12
Wednesday, Jun 11 - Aug 27
Sunday, Jun 22 - Sep 21
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)
AMC 10 Problem Series
Friday, May 9 - Aug 1
Sunday, Jun 1 - Aug 24
Thursday, Jun 12 - Aug 28
Tuesday, Jun 17 - Sep 2
Sunday, Jun 22 - Sep 21 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Monday, Jun 23 - Sep 15
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)
AMC 10 Final Fives
Sunday, May 11 - Jun 8
Tuesday, May 27 - Jun 17
Monday, Jun 30 - Jul 21
AMC 12 Problem Series
Tuesday, May 27 - Aug 12
Thursday, Jun 12 - Aug 28
Sunday, Jun 22 - Sep 21
Wednesday, Aug 6 - Oct 22
AMC 12 Final Fives
Sunday, May 18 - Jun 15
F=ma Problem Series
Wednesday, Jun 11 - Aug 27
WOOT Programs
Visit the pages linked for full schedule details for each of these programs!
MathWOOT Level 1
MathWOOT Level 2
ChemWOOT
CodeWOOT
PhysicsWOOT
Programming
Introduction to Programming with Python
Thursday, May 22 - Aug 7
Sunday, Jun 15 - Sep 14 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Tuesday, Jun 17 - Sep 2
Monday, Jun 30 - Sep 22
Intermediate Programming with Python
Sunday, Jun 1 - Aug 24
Monday, Jun 30 - Sep 22
USACO Bronze Problem Series
Tuesday, May 13 - Jul 29
Sunday, Jun 22 - Sep 1
Physics
Introduction to Physics
Wednesday, May 21 - Aug 6
Sunday, Jun 15 - Sep 14
Monday, Jun 23 - Sep 15
Physics 1: Mechanics
Thursday, May 22 - Oct 30
Monday, Jun 23 - Dec 15
Relativity
Sat & Sun, Apr 26 - Apr 27 (4:00 - 7:00 pm ET/1:00 - 4:00pm PT)
Mon, Tue, Wed & Thurs, Jun 23 - Jun 26 (meets every day of the week!)
0 replies
i Forum's purpose - Problem Index
parmenides51 18
N
Jul 10, 2024
by awesomelion7
I created this forum in order to post all the old *Russian Math Olympiads and complete the contest collections in the future, without spamming the existing forums with so many posts in so little time.
Here shall be posted all the old problems from 6 Math Olympiads:
- ASU (All Soviet Union) 1961-1992 (aops contest collection) (completed)
- All-Russian Olympiad Regional Round 1993- 2006: (aops contest collection)
- Chisinau City Math Olympiad (Moldova): (aops contest collection)
- Moscow Math Olympiads 1935-1997 (aops contest collection)
- Leningrad Math Olympiad (renamed to Saint Petersburg) (aops contest collection)
- Tournament of Towns 1980-1997,1999, 2000, 2011-14 (aops contest collection)
contest collections created so far: (inside this forum)
All Russian: 1961, 1962, 1963, 1964, 1965, 1966,
All Soviet Union (ASU) : 1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974 , 1975, 1976, 1977 , 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991
All Russian Regional: 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
Chisinau City MO (Moldova): 1949-56, (1957-72 got lost) , 1973, 1974, 1975 , 1976, 1977, 1978, 1979
Commonwealth of Independent States: ASU 1992
Moscow MO (ΜΜΟ): 1935, 1936, 1937, 1938, 1939, 1940, 1941, (1942-44 did not take place) 1945, 1946, 1947 ,1948, 1949, 1950, 1951, 1952, 1953, 1954, 1955, 1956 , 1957
Tournament of Towns (ΤοΤ): 1980 , 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988,1989, 1990, 1991, 1992, 1993, 1994, 1995 ,1996 ,1997 , 1998, 1999, 2000, 2004 ,2006 ,2008 , 2011, 2012, 2013,2019
extra
Leningrad 1965-92, 98 selected problems (besides Leningrad MO)
Moscow Mathematical Circles - 99 Selected Problems (MMCircles)
The following are problems we find most interesting among those offered to the participants of mathematical clubs, to the winners of the Moscow Olympiads when they were coached to International Olympiads and also some problems from the archives of the Moscow Olympiad jury which were not used in any of the tournaments, and, therefore, are not well known.
under construction:
MMO: 1958, 1959-97 (1942-44 did not take place)
ToT: 2014 , 2015, 2016, 2017, 2018, 2020
In every problem source, the problem's numbering is continuous through years
sources:
1.All Soviet Union MO
All Soviet Union Math Competitions 1961 - 1987 EN translated by S/W engineer Vladimir Pertsel (link)
All Soviet Union Mathematical Olympiad 1961-1992 EN with solutions, by John Scholes (Kalva) (link)
2. All-Russian Olympiad Regional MO
Всероссийских математических олимпиад школьников 1993–2006 (pdf)
3. Moscow City MO
60-odd YEARS of MOSCOW MATHEMATICAL OLYMPIADS, Edited by D. Leites (pdf)
Московские математические олимпиады. 1935 - 1957 г. (pdf here)
Московские математические олимпиады. 1958 - 1967 г. г (pdf here)
Московские математические олимпиады. 1981 - 1992 г. (pdf here)
4. Tournamenent of Towns
International Mathematical Tournamenent of Towns Book 1, 1980-1984 (AMT)
International Mathematical Tournamenent of Towns Book 2, 1984-1989 (AMT)
International Mathematical Tournamenent of Towns Book 3, 1989-1993 (AMT)
International Mathematical Tournamenent of Towns Book 4, 1993-1997 (AMT)
International Mathematical Tournamenent of Towns Book 5, 1997-2002 (AMT)
5. Chisinau City MO
Кишиневские математические олимпиады Ю.М.Рябухин 1983
6. Leningrad proposed problems
Санкт-Петербургские математические олимпиады by Фомин Д. В. (1961-93)
Related forums:
Old High School Olympiads
China High School Contests
KöMaL (Hungarian Magazine)
For the friends of Geometry:
Olympiad Geometry Collections + Forums
A Beautiful Journey Through Olympiad Geometry - solutions forum
Evan Chen's EGMO study group
Lemmas in Olympiad Geometry - active forum
Tran Quang Hung's geometry group
PS. A Forum Collection for Aops Geo Mocks,
* Here Russian stands for ex - USSR countries.
Here shall be posted all the old problems from 6 Math Olympiads:
- ASU (All Soviet Union) 1961-1992 (aops contest collection) (completed)
- All-Russian Olympiad Regional Round 1993- 2006: (aops contest collection)
- Chisinau City Math Olympiad (Moldova): (aops contest collection)
- Moscow Math Olympiads 1935-1997 (aops contest collection)
- Leningrad Math Olympiad (renamed to Saint Petersburg) (aops contest collection)
- Tournament of Towns 1980-1997,1999, 2000, 2011-14 (aops contest collection)
contest collections created so far: (inside this forum)
All Russian: 1961, 1962, 1963, 1964, 1965, 1966,
All Soviet Union (ASU) : 1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974 , 1975, 1976, 1977 , 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991
All Russian Regional: 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
Chisinau City MO (Moldova): 1949-56, (1957-72 got lost) , 1973, 1974, 1975 , 1976, 1977, 1978, 1979
Commonwealth of Independent States: ASU 1992
Moscow MO (ΜΜΟ): 1935, 1936, 1937, 1938, 1939, 1940, 1941, (1942-44 did not take place) 1945, 1946, 1947 ,1948, 1949, 1950, 1951, 1952, 1953, 1954, 1955, 1956 , 1957
Tournament of Towns (ΤοΤ): 1980 , 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988,1989, 1990, 1991, 1992, 1993, 1994, 1995 ,1996 ,1997 , 1998, 1999, 2000, 2004 ,2006 ,2008 , 2011, 2012, 2013,2019
extra


The following are problems we find most interesting among those offered to the participants of mathematical clubs, to the winners of the Moscow Olympiads when they were coached to International Olympiads and also some problems from the archives of the Moscow Olympiad jury which were not used in any of the tournaments, and, therefore, are not well known.
under construction:
MMO: 1958, 1959-97 (1942-44 did not take place)
ToT: 2014 , 2015, 2016, 2017, 2018, 2020
In every problem source, the problem's numbering is continuous through years
sources:
1.All Soviet Union MO


2. All-Russian Olympiad Regional MO

3. Moscow City MO




4. Tournamenent of Towns





5. Chisinau City MO

6. Leningrad proposed problems

Related forums:
Old High School Olympiads
China High School Contests
KöMaL (Hungarian Magazine)
For the friends of Geometry:
Olympiad Geometry Collections + Forums
A Beautiful Journey Through Olympiad Geometry - solutions forum
Evan Chen's EGMO study group
Lemmas in Olympiad Geometry - active forum
Tran Quang Hung's geometry group
PS. A Forum Collection for Aops Geo Mocks,
* Here Russian stands for ex - USSR countries.
18 replies
x^2 + ax + b, x^2 + cx + d - All-Russian MO 1996 Regional (R4) 9.1
parmenides51 1
N
Apr 17, 2025
by Mathzeus1024
Find all pairs of square trinomials
,
such that
and
are the roots of the second trinomial,
and
are the roots of the first.






1 reply
sum 1/\sqrt{1+x^2} <=2/\sqrt{1+xy} - All-Russian MO 2000 Regional (R4) 11.5
parmenides51 1
N
Apr 17, 2025
by Mathzeus1024
For non-negative numbers
and
not exceeding
, prove that




1 reply
| sin nx| >= \sqrt3 / 2 - All-Russian MO 2006 Regional (R4) 10.5
parmenides51 1
N
Apr 17, 2025
by Mathzeus1024
Prove that for every
such that
, there is such natural
, which




1 reply
Ice cream costs 2000 rubles - All-Russian MO 1996 Regional (R4) 8.1
parmenides51 1
N
Apr 15, 2025
by Mathzeus1024
Ice cream costs
rubles. Petya has
rubles. Does Petya have enough money for ice cream?


1 reply
ASU 550 All Soviet Union MO 1991 100x100 array, equal product each column
parmenides51 2
N
Apr 15, 2025
by zhoujef000
a)
are distinct reals. The number
is written in position
of a
array. The product of the numbers in each column is
. Show that the product of the numbers in each row is
.
b)
are distinct reals. The number
is written in position
of a
array. The product of the numbers in each column is the same. Show that the product of the numbers in each row is also the same.






b)




2 replies
ax^2+bx+c, (c-b)x^2 + (c- a)x +(a + b) - All-Russian MO 2001 Regional (R4) 10.5
parmenides51 1
N
Apr 15, 2025
by Mathzeus1024
Given integers
,
and
,
. It is known that the square trinomials
and
have a common root (not necessarily integer). Prove that
is divisible by
.








1 reply
cosa+cosb+cosc>sina+sinb+sinc- All-Russian MO 2004 Regional (R4) 10.1
parmenides51 1
N
Apr 15, 2025
by Mathzeus1024
The sum of positive numbers
is equal to
. Prove that



1 reply
MMO 372 Moscow MO 1957 divide a_i <= a_{i+1} <= 2a_i, into 2 groups
parmenides51 10
N
Apr 14, 2025
by InterLoop
Given
integers
such that
(
) and whose sum is even. Find whether it is possible to divide them into two groups so that the sum of numbers in one group is equal to the sum of numbers in the other group.




10 replies
Help needed
JetFire008 2
N
Apr 5, 2025
by JetFire008
Does there exist a finite set
of nonzero real numbers, such that for any natural number
a polynomial of degree no less than
with coefficients in
, all of whose roots are real and belong to
?
Can someone explain the solution of this question?





Can someone explain the solution of this question?
2 replies
TOT 377 1993 Spring A S5 piecewise linear function f(f(x)) = -x
parmenides51 1
N
Mar 26, 2025
by jasperE3
Does there exist a piecewise linear function
defined on the segment [
(including the ends) such that
for all x? (A function is called piecewise linear if its graph is the union of a finite set of points and intervals; it may be discontinuous).

![$-1,1]$](http://latex.artofproblemsolving.com/9/8/8/988b44fd7f73ec681f289049ed9a181549f3590a.png)

1 reply
