#competition-math
1 messages · Page 27 of 1
like you can consider their projections onto face GFEH
that's the easy part tbh
you have the volume above the plane z = 1.5 and the volume below the plane z = 1.5
Don’t use graphs stuffs
then just use similarity on ABCDG and EFGHP
I don’t know those 3d graphics lol
it's sufficient to graph in 2D by symmetry
Where is z
Okay
I see what u mean
Those 2 small pyramid is similar to the whole pyramid?
yes
because the shape is a square in the middle of the cube
well that's the length ratio not the volume ratio
The volume ratio is 1:8
R?
great and (1:4)^3 = 1:64 is the volume ratio for the other one
72+36-9/2-9/8=102.375?
And that is the final answer?
,calc (1/3 * 6 * 6 * 3) * 1/4 + (1/3 * 6 * 6 * 6) * 1/64
Result:
10.125
well
Should be *1/8 right?
wait no, the square base isn't 1.5 by 1.5 right, let me think
hold on
the problem is where PE cuts GD
The base is a rectangle?
so for AG, FP and PH, GC, yeah I set up the equations wrong
should be y = x and y = 3 - x/2, so that implies y (the height) is 2
yeah seems like it
yeah and then for PE, GC it would be:
P = (0, 0, 3), E = (6, -6, 0), G = (0, 0, 0), D = (6, -6, 6)
I am cooked with 3d
yeah so the height is again 2
I made a silly error: okay it was a square base, but the height is 2 instead
So the upper one is 1
so yeah the volume ratios are (1/3)^3 and (2/6)^3 respectively
I got 104
,calc (1/3 * 6 * 6 * 3) * 1/27 + (1/3 * 6 * 6 * 6) * 1/27
Result:
4
Oh btw how u get 2 using y=-1/2x+3?
y = -1/2 x + 3 and y = x
like consider P = (0, 3), H = (6, 0), G = (0, 0) and C = (6, 6)
then PH and GC, their intersection
And then?
Find the distance?
Oh wait I got it
Because they are similar
So 3:6=1:2
I have a solution I think that works, hopefully. Solution: || Consider the cross section of the wanted 3D region that has its corners of the four other corners (the ones of the 3D region other than P and G). Notice that this cross section has to be a square and that we can cut the 3D region into two square based pyramids that are glued together by the same square base with side length of a. The bottom pyramid is similar to pyramid ABCDG and the top pyramid is similar to pyramid EFGHP clearly. Also notice that the sum of the heights of the two pyramids is PG, so the volume becomes (1/3) * a^2 * 3 since PG is clearly 3, hence the volume is a^2. Now consider plane ABGF to be in the x-y plane where F is the origin, G = (6,0), A=(0,6) and B=(6,6). Notice that equation AG is 6-x and equation FP is (1/2)x, so their intersection is at coordinate (4,2). The distance from this intersection to FG is 2, so therefore the height of the bottom pyramid is 2. Then use similar triangles to see that 2/a = 6/6 = 1 by considering the cross section of the 3D region that is parallel to side ADEF that makes a triangle in the bottom pyramid that is similar to BCG. Therefor a=2 and thus the wanted volume of the 3d region is 4 ||. Hope this helps
Nice problem!
Yo if i am travelling to point A to point B on the same quadrant but must touch the x axis, how come the problem can be simplified wiht a reflection of point B over the x axis
i can see it intuitively with the drawing and lines but im wondering what the rigorous arugment is
triangle inequality
the distance from A to the point you touch on the x axis equals the distance from the reflection of A to that same point
from there argue that the shortest path from A to B has the same length as the shortest path from reflected A to B (which is just a straight line, must be shortest by triangle inequality)
hi
Do you think they're worth the price, and if I'm not taking a course would you recommend getting one of the books, are they more about text or interesting problems?
If you’re going from point A to point B, and you must touch the x-axis along the way, then you’re essentially looking for a path that starts at A, touches the x-axis somewhere, and ends at B. You can just reflect point B over the x-axis to get point B’
If everything is +, I know that the total is 1012 * 2025. Besides that, I know that when a number n is negative and we make it positive, it adds 2n and when n is positive and we make it negative, it removes 2n from the total sum, but I don't know how to proceed
the thing covers all evens from -1012*2025 up to 1012*2025
Oh, and 1012 * 2025 mod 2024 = 1012 right, so the remainders for 1 <= i <= 2024 are 1010, 1008, 1006, ..., 2, 0, 2022, 2020..., 1012 right
So the answer is 1012
cool
8 is 2/3
!noans
The purpose of this server is to help you learn, not to hand out answers. Do not ask someone to give you the answer directly.
7,8 are not contest level problems, wrong channel
12 also debatably not contest level either
@left axle Can I guide you kindly in solving the problems?
I can get b/w 160-180 marks in JEE Advanced is it enough?
Yall r really advanced..
Oh tysm but I figured it out
AFGE = GEBH = EDHC = 1cm^2
How do I prove that GJI's height = GIB's height
The solution for the problem says so, but it doesn't give any explanation
If you want to see the problem, here you go
is time a constraint while solving this problem?
Yes
how much time is available?
2h and 30min for 5 questions, so 30 minutes for this one
not too much at all actually
lol
i have one very dumb approach, set B as origin and use coordinate geometry
This olympiad targets students that probably aren't familiarized with this one
oh, then it will be quite difficult
Not at all, I have already solved knowing that the heights are equal if you want to see
I just don't understand why the heights are equal
sorry man, i'll try but it may take me days, so don't expect a response now
Help
can you tell me corresponding to which side the height you're talking about?
GIJ height's corresponding to GJ and GIB height's corresponding to GB
take a general 3x3 magic square, what do you notice about all the sums going through the middle square?
They are all the same
Interesting Question: Connecting Laws of Logarithms to an application in magic square. Do you realize that you will use all the rows (Row 1, 2, 3); all the columns (Column 1, 2, 3); the two diagonals (Left Diagonal and Right Diagonal) to determine <i>x, y, z</i> in terms of <i>a, b, c</i>
Here is the detailed solution: Number (3.) on
https://examssuccess.appspot.com/MATHEMATICS/ExponentsLogarithms.html#one-twenty
These are the solutions to Mathematics questions on topics in Exponents and Logarithms.
I see im just getting tired of writing those equations in terms of other equations
Thank you mathematics guy
When you have multiple equations, and you need to use more than one equation, then I guess you have to do it.
I see
You are welcome. Let me know if you have any question based on the solution.
Do u have the full process for solving this question?
Wait nvm I saw it on the website
Yes Sir...I think I explained my work clearly. Let me know otherwise.
Why we pick row 1 and row2 , column 1 right diagonal, left diagonal and column 3…….
We need to use all the rows, all the columns, and the two diagonals because we have to equate rows to columns, columns to rows, rows to diagonals, etc. (based on the definition of a magic square that the sum of each row, each column, and each diagonal is the same). We are given these variables: $x, y, z, a, b, c, p, q, r$ but we only need $x, y, z, a, b, c$. We do not need $p, q, r$ So, how can we isolate p, q, r in our work?
The Mathematics Guy
Okay thx
Guys, has anyone read Evan Chen's OTIS-Excerpts? Did you like it?
why don’t you read it yourself and form your own opinion
An enemy submarine determined to sink your ship is sitting, torpedoes armed, exactly halfway between you and your home port. The submarine submerges to some fixed depth, and your ship now has no further information about its position. The enemy sub has to be directly underneath your ship to sink it — but the sub can track your moves with precision and respond efficiently. If your ship is fast enough, though, you will be able to set a wide course around the sub and reach port safely.
How much faster than the sub does your ship have to be to guarantee you can avoid the sub and get home?
The Mushroom Kingdom is a kingdom in the shape of a equilateral triangle with sidelength $2024$ units. The large triangle is divided into $2024^2$ unit triangles where each unit triangle is a city. One day, Bowser attacked the Mushroom Kingdom. He sends an army of Koopas to colonize $4048$ cities in Mushroom Kingdom. It is known that for every four cities that form an equilateral triangle with side lengths 2 units, if three cities in the triangle have been colonized, then the fourth city will also be colonized. This continues until Bowser can no longer colonize cities in the Mushroom Kingdom. Can Bowser choose $4048$ cities that will be colonized first, so that he can successfully colonize the entire Mushroom kingdom?
1Bazan
Wth
There's a starting configuration with 3·2024-3 cities that works, butt 4048 appears to be a tall order.
Let $x,y,z$ with $x^3+5y^3=25y^3$. Prove that $x=y=z=0$. Can anyone give me a really light hint?
ProjectTime
have you thought about divibility by 5 yet?
🙏
Oh my fricking goodness
So ingrossed in mod I forgot about that
thank you
oh my
this proof method is called ||infinite descent, and was used by fermat in proving Fermat's little theorem when n=4||
Then it's just the infinite
desnetn
This bad boy was the final problem in a section about mods
oh my
I think aops v1 and v2 covers it deep down if you really throughly solve the problems
Is there a prime Kaprekar number? Not Kaprekar constant, I mean number like 1, 9, 45, 55, 99... Is there a prime one?
hi
peles help me
I have a problem. I'm trying to solve time flexibility with math. We have a vision of a series of numbers that are repeating or a series of decimal numbers that are not divisible by anything at all.
p= 2X *9m =- 11
11 -= 0m + mp2 - 29 = 2.7580088765936458
OM = 0 -9 *1.2 + 0.4
mp = 8 + 7 * 78 - 3
and
x =?
m == X-2 * 82 ms
AoPS 1 and 2 are horribly insufficient on their own
the contest scene was way less competitive 30 years ago when those were written
lots of content holes, problems aren’t hard enough, etc
think of it more as a survey of the most common contest techniques than actual intensive training on any of them
Yes, there exists at least one prime Kaprekar number. An example is the 764th Kaprekar number which is 1111111111111111111 (has 19 1’s in its decimal representation), and is apparently the smallest Kaprekar prime. Proof is that 1111111111111111111^2 = 1234567901234567900987654320987654321 and 123456790123456790 + 0987654320987654321 = 1111111111111111111. The first number in the sum has 18 digits and the second number in the sum has 19 digits. This is using the definition of a Kaprekar number that if you have a number of n digits which we call k, and when you square k and add the right n digits to the left n or n-1 digits it equals to k, then it’s a Kaprekar number
I mean for AMC level they are solid as those have not changed much. i always thought aops 1 covered AMC 8-10 and aops 2 AMC 12 to early aime.
As far as resources though titu from awesome math is always cranking out new books that are solid in particular topics
Did you guys do the gauss math contest
CEMC time
Is the answer 16?
No
Break down by casework
||Notice that the number of tiles forces you to have 2 vertical 2x1 white blocks, after pairing each white tile with a black tile vertically. The remaining tiles must fit a checkerboard pattern. Depending on the position of these vertical white tiles, you can have 1, 2 or 3 checkerboards. Each checkerboard can have a vertical reflection. There are (13 choose 2) = 78 arrangements up to vertical reflection of checkerboards.
Cases:
1 checkerboard: 1 x w…w, 2 x ww…, giving 3 cases
2 checkerboards: 2 x 10 x w…w… + 10 x …ww… giving 2x10+10=30 cases
3 checkerboards: remaining 78-33=45 cases
Total: 3x2^1+30x2^2+45x2^3=486||
Yeah I have....I think they are good..should do!
Why 13 choose 2?
hi, I just finished taking ap precalc and found it pretty easy with a grade of 99%, but competition math like AMC freaks me out and seems so different. how can i practice for competition math?
- AP is a complete joke difficulty wise im not surprised in the slightest that that’s not sufficient preparation for contests
- AoPS has a wealth of resources for learning contest math including lots and lots of past contest problems from around the world
Why not opt b ( helpp !!)
need to correct for overcounting
for example what if in the initial 8 I pick red ball 1 and red ball 2 from box 1, then I pick red ball 3 in the final 2
or what if I instead pick red ball 2 and red ball 3 first, then red ball 1
@tribal fog most notably they have every past AMC contest there is on their website, super useful when you want to practice under test conditions
Ok, thank you
np
ull have to make cases
like C1) you pick 4 balls from one box and 2 balls from the other boxes
and C2) in 2 boxes u pick 3 balls and 2 balls from other 2 boxes
another hint ||while picking 3 balls u can just pick any 3 at random and subtract 1 case for when u pick only 3 red balls||
13 choose 2 is because there are 13 vertical 2 by 1 blocks in total. Like the other person said, since there are 11 black tiles used this forces 11 of the vertical blocks to contain a black square (each column must have either one black square (and thus also one white square) or no black squares (which is the same as having two white squares)). Therefore the remaining 13-11 = 2 vertical blocks are fully white. The number of ways of of picking 2 distinct vertical blocks out of the entire 13 vertical blocks is 13 choose 2.
is there like any other way ? rather than calculating all the cases?
for this too , is making cases the only option?
someone help please
i could do the (a) part, but i have no idea how do i even start (b) part
i think a combination of recursion and induction might help, but i'm unable to convert this into something meaningful
If the tallest student arrives first and takes his place, and then the next tallest, and so forth, then:
a) the badness is only ever increasing.
b) the badness after a student arrives depends only of what the badness was before and where in the line-so-far the arriving student ends up standing. It doesn't depend on any other knowledge of the line-so-far.
This should at least enable an O(nk) dynamic-programming algorithm for g_k(n), and possibly also a closed form if you write down the recurrence without any distracting details about lines and heights.
not that i can think of
and i think there should be only 2 cases
so its really not that bad
okayyy, thankyouu
also note when you are picking from boxes like in this case pick from one box only once or else ull have some cases of double counting
I can’t use programming algorithms, this is from an undergrad subjective math exam
My hope would then be that writing down the recursion explicitly (which I haven't bothered to myself) might inspire a closed-form formula.
yeahhhh I tried that
I tried defining a recursive function for n and n-1 orderings
if f(k,n) counts all orderings with badness <=k and f(k-1,n) counts all orderings with badness <=k-1
then their difference should give me g(k,n)
but how do I calculate f(k,n) 😭
I would go for a formula for g(k,n) directly.
Something like g(k,n) = (sum for k<j<n-1 of g(j,n-1)) + (sum for 0<j<=k of g(k,n-1))
where the second term immediately simplifies to k·g(k,n-1).
that sounds just as hard—
If nothing else, it would make it possible to compute values up to n=5 or so by hand, and look for patterns.
heyy guys wanna try out this problem, its a toughie @everyone
represent it as cot(a+kb)-cot(a+(k-1)b), then telescoping summation
Clever.
This is the third time I am seeing it on this server🐿️
Got it thx
This is the detailed solution:
Number (7.) on https://examssuccess.appspot.com/MATHEMATICS/Trigonometry.html
Please let me know if you have any question on the solution/explanations.
These are the solutions to Mathematics questions on topics in Trigonometry.
Mods
Wow, that is a very long explanation that almost hides the forest among trees. It would be shorter and clearer just to say something like:
Note that in general, as long as we don't run into division by zero,
$$ \frac{1}{\sin(\alpha)\sin(\beta)} = \frac{1}{\sin(\beta-\alpha)}(\cot(\alpha) - \cot(\beta)) $$
(Namely expand $\cot$ to $\cos/\sin$, put on a common denominator, while separately using the angle-difference formula on $\sin(\beta-\alpha)$.)
In this particular series, $\beta-\alpha$ is just the constant $\pi/6$, and the $\beta$ becomes the $\alpha$ of the next term, so the this rewriting makes the series into
$$ \frac{1}{\sin(\pi/6)} \sum_{k=1}^{13} \cot\left(\frac\pi4 + \frac{(k-1)\pi}6\right) - \cot\left(\frac\pi 4+\frac{k\pi}{6}\right) $$
which telescopes.
Troposphere
Is anyone else doing ACSL?
(π/4 +kπ/6)=t
for simplicity
then multiply divide by sinπ/6
write that as sin(t+π/6-t)
sin[t-(t-π/6)]
then use sin(A-B)=sinAcosB-cosAsinB
mathematical olympiads
yes
i wanna form a study plan for a math competition
basic low-level math competition, nothing crazy
how do i make one?
should i show an example question?
What competition
this almost sounds gpt’d 😭
Only almost. GPT would blather on about what it's doing in long tedious complete sentences. This one is just formula upon formula with only short headlinese hints about how they relate to each other. Looks human to me ...
reminds me of all those enshittified “homework help” sites shortly before GPT slop took over them
Did you "really" look at my solution? Wow...
consider improving your prose to not be so full of fluff
Someone was even complaining of my "long" explanations without considering others who may review the same solution.
Look at my explanations. Then look at your explanations. Compare the two and show them to anyone. Then, ask the person which one is "more clearly" explained.
You did not even appreciate the fact that I verified the solution with a calculator.
ok what does calculator verification have to do with anything
If you have questions on my solution, ask. Otherwise your criticisms does not help.
if you’re obfuscating the key ideas of the solution behind unmotivated formula spam then that’s not an effectively communicated solution
Verifying your solutions with TI-Calculator is important...if you are allowed to use a calculator. No one told you that?
it’s entirely unnecessary fluff if your procedure is correct
you shouldn’t need that
I have noted your name. I shall not attempt any question you post anywhere in any chat.
ok and
cry about it
there is no need to LIST EVERY SINGLE TRIG FORMULA UNDER THE SUN just to preface the solution of one problem
I shall not argue with you regarding verification with a calculator. It's common sense that if you are allowed a calculator, then you should verify your work with the calculator functions.
Tell me one formula I listed that is unnecessary...just one
Look at that solution and just screenshot one formula I used that is unnecessary...tell me just one.
oh whoops didn’t realize all the actual solutions were buried under that mountain of text
suggestion; add an option to hide/show the formula list
Also, there is no need to type in uppercase letters. I am asking you for one "unnecessary" formula that I used...list only one
ok my bad I didn’t realize that formula list wasn’t part of any one solution
but still if you’re able to id suggest adding a hide/show option for them
And for the other person that criticized my explanations, we do not need to argue. Show my work and your work (the one you typed) to any person: student, teacher, etc. Then ask them to tell you whicb one gave clear explanations. Show both works to "diverse" student and teacher population (those with varying degrees of mathematical abilities).
You write a formula before you use it. You do not list all the formulas that you will use before you begin to solve. As you solve each step, you write the formula needed, then you use it.
Did you notice the dotted lines I used to separate sections of my work?
I do Mathematics for fun and to help people. However, when anyone does not provide constructive criticism, I will just avoid anything that person posts.
you just sound butthurt that people aren’t blindly praising your solutions
Constructive criticism is welcome. But destructive criticism is not welcome.
that doesn’t mean you can just outright ignore it lmfao
and now having read the solution I do have some technical issues with it:
You said there is no need to list every trig formula. But any formula I listed is necessary for "all" categories of learners. I do not write solutions for only the mathematically fast learners. I write solutions in a way that anyone who reads it understand what I did.
Assumed numerator implies that it is not the numerator in the "original" question. I have to do some modifications to get the telescoping series. Hence, I used the word, "assumed" because some people might be confused if I used only "numerator"
what are you assuming? why are you assuming it?
until I read troposphere’s paraphrased solution it wasn’t clear that you were trying to get sin(pi/6) in the denominator and something that can telescope in the numerator
I am assuming it because I cannot solve the expression in the original form. I have to do some modifications.
I cannot just write sin(pi/6) without explaining how I got it
then explain that more clearly
I write solutions so that "anyone" who reads it will understand. Did you really look at my "entire" solution? I showed "all" work
you showed it all but didn’t explain it clearly
If you look at all the questions I have solved in this chat (and other chats), I show "all" work. I do it to accommodate everyone...no matter your level of mathematical ability
you can list all the arithmetic steps you want but if you don’t explain what you’re doing with each one people still risk getting lost
Please screenshow what I did not explain clearly. I am a lifelong learner. I want to improve based on your comments.
Screenshot and paste what I did not explain well.
“seeing the product of sines in the denominator, we think to apply product-to-sum in order to express the summand in a form that telescopes…”
more clearly emphasize here that the overarching goal is to make the series telescope
the whole “numerator/denominator” steps are also not explained well
My dear, did you miss this?
May you please let me know what is not explained well?
you just throw a wall of equations at the reader without enough explanation
sure you say you want the sum to telescope, but how will you achieve that?
May I ask you: did you understand what I did? Please be honest.
with some effort
It's a "yes" or "no" answer. Please tell me.
yes
Okay. I am waiting for anyone who did not understand it.
I just think it is very poorly presented
I wrote that anyone who did not understand it should let me know.
the technical details are fine but could be communicated/organized better
May you write your work in that regard on how it should be presented?
sure
^ I prefer the style of invoking formulae/theorems when required
all the actual problems are just buried under the formula list
from a UX perspective that’s not ideal
I’m not sure what it looks like on laptop but yeah it’s kinda unreadable on mobile imo
If anyone has any question about my work, please let me know. Do not mind @pallid tundra because he/she stated already that he/she understood it.
Mathematics work involving latex is best read on a computer, not on a phone.
Agreed
But that doesn’t mean it should be unreadable on a phone either
It is not unreadable on the phone. The screensize of the phone matters because some work is lengthy on a single line
Some formulas are lengthy on a single line.
Can you read my work on a computer and let me know if it makes sense or not?
Some things like ‘pneumonics to remember the quadrants’ are redundant
Regardless of how you read it
An answer should explain the process, a different type of resource is needed to actually learn the content
You mean this pneumonic? What is wrong with it?
Poeple have different mathematical abilities regardless of the resource they used to learn the content. Do you agree?
It takes up space and is unnecessary
Which means it takes longer to get to the answer
So it’s difficult to keep the flow of logic in the mind
That’s why it’s nicer to invoke theorems on the step you need them
(Or trig values or quadrants in this case)
If I understand you clearly, you are saying I should not write the pneumonic. Is that correct?
Yes
But did you understand my solution to the question posted by @near hill ?
Did you understand the explanations?
You are missing the point
The explanation can be perfect but it doesn’t help if there’s a wall of redundant text before it
And I haven’t read the explanation because it’s so much effort filtering what is and isn’t helpful
I got to that table and quadrant part and gave up
Did you see that link: Numbers 1 - 20?
If you click on that link, it takes you directly to the questions and the solutions.
Ah I didn’t, that’s probably a phone thing. Can you not make the link go directly to there?
That helps a bit but I still would give the same advice
Yes Sir, I just posted the direct link to the question.
May I explain the reasons for having that pneumonic?
As I write each step of a solution, say I need to use 3rd Quadrant Identity
One of my readers may ask: what is 3rd Quadrant Identity?
That reader may not have heard of that term before reviewing my solution.
Hence, that reader needs to see it there on the page to help him/her understand. Do you understand what I mean?
I give you another example.
For all problems I do on Circle Theorems, I give a reason for each step.
I’d say that the way you memorise values is up to you
Why would you force the reader to understand your memorisation of angles
If my reason is not found on that page, it may confuse some students. Do you not think so?
Why not just focus on the result and not how you memorise it
Oh another point is just vary the text size and colour
It’s makes it way easier to read the solution
My dear, I am trying to help people. I am not forcing anyone to memorize angles.
You’re forcing them to understand the way you were taught
I don’t use pneumonics for example
So that’s just a pain for me
Have you ever used pneumonics for anything?
Yes. I wouldn’t expect an answer sheet to list it
guys when they say limit exists we shud check if RHL=LHL=f(a) right?
If you can’t remember something that’s a different problem
If it’s defined both sides then generally it’s better to
Yes, Left Hand Limit should be equal to the Right Hand Limit
so what do they mean by LHL exists or RHl exists
I should really reply: yes, and I know other people use other ones
Because that’s the problem
like this question
It converges <==> it exists kinda
“left hand limit” is the limit as x increases towards that value
(Well is a limit to infinity ‘existent’ actually idk)
you’re “approaching from the left”
what do u mean converges
Oh boy
similarly “right hand limit” is the limit as x decreases towards it
i understand that
Probably don’t worry about it 🤣
Simply, converges means it gets as close as possible to a value
fair
But if you think about 1/x near 0, it gets faster and faster and doesn’t reach anything
biggest advice is to state upfront what you’re hoping to prove
so basically what i have to check if lhl and rhl are finte or not?
something like “we claim that $\frac{1}{\sin\alpha\sin\beta}=\frac{\cot\alpha-\cot\beta}{\sin(\beta-\alpha)}$” and then follow it with a proof of the identity
elrichardo1337
Thank you, much better way of speaking my thoughts
The justification should come after the statement
Or alongside
here you’re supposed to recognize it as the common trig limit $\lim_{x\to 0}\frac{\sin x}{x}=1$
elrichardo1337
or wait
things are a bit trickier here bc of the sign issues
but try to express it in terms of that known limit
so basically what i got is lhl=+inf and rhl=0
but i dont know which option is correct
by doing this the reader now knows why you’re going through the computations you do
thanks i guess
What is actually competition-math is? why does it really unique
The depth of problem solving goes significantly beyond the school curriculum
You may also encounter topics that you haven't seen before
so is it just more Into problem solving
or just speed
or both?
Speed isn't that important especially at higher levels
low level contests are more speed based (read: computation focused)
while technically they’re all non calculus they nonetheless involve some highly nontrivial stuff
most of which is excluded from standard k-12 curricula
what competitions are happening for 8th graders
ohh i see okee thanks
in the US the two big middle school contests are MATHCOUNTS and AMC 8
check also for other regional and/or online contests
well maybe they used to be big
erm its like geometry stuff and algebra stuff 
MATHCOUNTS lost like 75-80% of their participants after 2020 and never recovered
and number theory, and combo
essentially the four olympiad topics but uhh one could say dumbed-down or say lower in difficulty at least i think so
Evaluate this limit without using l'hôpital rule
wrong channel
It's a challenge , i don't need help
I know, but you should still post in #precalculus and not this channel
also tell people it's a challenge
otherwise you're leading people to waste their effort
if they already know how
they said they didn't need help....
is it 0?
No
This is not a precalculus limits is really hard
And why doing olympiad at the first place it just a waste of time
limits at the “AP calculus” level are completely trivial bruh 😭
ok and
the audacity u had to tell this in maths discord sevrer in the competetion channel is crazy
And ? That your problem bro
nah just a compiment i cud never
I'm just sending it for anyone interested
I think it could easily become your problem if you insist on hanging around in a topic channel just to tell people that the topic of the channel is a waste of time ...
It not like the previous post interested me but i kept quiet but when i shared a fun limit i get hate for no reason
I don't want to debate for now
There might be someone interested in solving this limit i'm not sending it for anyone specific idk why i get all this negative response for nothing
You're getting negative responses because you're posting a problem that doesn't look like a competition problem in the competition-math channel.
Well try to solve it first , were you able ?
Whether or not I can solve it doesn't have any bearing on whether it looks like a competition problem or not.
What a competition problem for you a sommation then doing a little telescoping action ?
You can literally give him any sort of sommation and he will count it as an olympiad , and don't let me talk about pigma this will break his mind
??
HOW MANY HOURS YALL PRACTICE PER DAY
40
🫑
substitute x=t^6 and do it the usual way. Factor out 1-t and then cancel it. You get -1/12.
Yep you're right
For any non-negative reals a≥b≥c≥d satisfying ab+bc+cd+da=4, is it always true that a+b+c+d≥4?
Let x=a+c and y=b+d. Then xy=4, so x+y≥2√(xy)=4
1+1=2
damn such a clean observation
impeccably outstanding
Am I doing it correctly?
(This is really not a computation you need to render with TeX to make it readable, I think.)
$$\ p^2 + q^2 = r^2$$
$$\ a^2 = 2 * p^2$$
$$\ b^2 = 2 * q^2$$
$$\ c^2 = 2 * r ^ 2$$
$$\ a^2 + b ^ 2 = 2 * ( p^2 + q ^2 ) = 2 * r^2 = c^2$$
Angular | Ionic Dev
||the triangle with side lengths a, b, c is similar to the central triangle (all lengths scaled up by sqrt2), done||
does anyone wanna try some of my homemade questions
what site is this
hm
oare you fine with spoilers?
nobody gave a correct solution yet
sure
Invented this problem 5 days ago
Am craving for a solution
thats when we drop two eggs of consecutive hardness from the same floor
so, let us say after a throw from height a-1, the possible set of weights is [b,...,c]
then before it, the possible set of weights before is [ab,....,ac]
with n = 1, any m is enough
and n = 2 m>= 3
we drop the each two eggs from floor 1 and 2
The one that breaks is 1 and the one that does not is 2
oh yea right
but above that i cant make it work
whatever you are cooking please tell it next day
im feeling very sleeply
also consider posting your solution in https://artofproblemsolving.com/community/u1185903h3579317p34960010
n = 3,2,1
2 is useless
2 -> 3,1 2,0 1,0
1 -> 3,1 2,1 1,0
drop something from 1, if it breaks then its 0
if it doesnt break, it is currently 1, we have one more one, and we have a number we are trying to find out
we cant drop the number we are interested in from floor 1, otherwise we lose information
hence drop another egg from floor 2, if it doesnt break, it was 3, we started with a 2, and ther last egg is 1, if it breaks, then we either dropped a 1, or we dropped a 2, and so the possible outputs are (1,0,2) (1,0,3) (1,0,1), now we cant figure out what state the last egg is in, so it is impossible
this qn is impossible
i dont use aops much
oh ok
also, i am embarrased to say, but idk latex
neither do i i just use chatgpt
oh
but if it is impossible to find the correct order there must be a proof
i gave proof
for n = 3
for n > 3, n = 3 is a subproblem that must be solved
so it is impossible
we could carry on induction
oh ok
its kind of sad man to see my problem having this easy sol
anyway thanks
trust me, its worse when your prob has no sol
i once made a random prime number prob
gtg bye
bye
wait tell me the problem
i forgot
but i asked a sir
oh yeh i remember
show, or prove false, there are infinitely many primes numbers which are a distance of 1 from the product of the first n primes for some n
watch your spelling
there are probably a good deal of online competitions out there
the most highly respected international competition for high schoolers is IMO
imo imo imo imo
what other competitions are well known among the universities?
unis don't care about contests in general
hmm
except as extracurriculars for the purposes of admission, but I mean that's not a requirement at all, nor do most successful mathematicians need contest maths
yeah, its for admission purpose
but I mean the specific contest doesn't matter
if you can't get into IMO, at least try to qualify for a regional olympiad, then a national olympiad or continental olympiad
then if you do well
being on your country's training team is already a big accomplishment
How do i actually practice the problems
I feel demotivated everytime i fail
And dont want to sit and do it when i fail
its okay
normally i take a break when i fail to solve a problem
but i atleast make sure i gave it my best try and also that i understood its solution
oh
I dont, maybe thats the problem
But i still dont understand how people come up with elegant solution
its just they spend too much time with the problem
i go up halfway then my brain halts
Well i cant even solve pre regional level problems
unless its a easy problem i dont even know how to approach it
same
lol
me too
haha lol
Which class are you studying in
i gave ioqm last year
9th
Same
Oo im in 10th
so did you qual?
nope, i only got 12
oh its ok
did u qual?
since we both started early maybe we can atleast attend imotc before college
Hopefully
yes barely i got 33 cutoff 32
oo nice
thanks
and its not like all mathematicians are inmo awardees
same lol
But you got 33
So you are atleast way better than me, I need tips XD
For example this how tf am I gonna aproach
yea sure first of all do you have a excursion in mathematics?
I have all the books
Burton, Excursion, Hall and knight, Pre college, Mcgraw hills IIT, u say it
hall and knight isnt of much use
Algebra?
tho a bit overkill for ioqm
Is it beginner friendly though
no
.
so do you take coaching anywhere?
nope
hmmmmm, alr
Assam
Hmm
vendantu olympiad school
Alr
Alr
im not telling you to enroll there
the YT channel?
just watch their youtube vids
yes
like Those random IOQM videos that pop up
they explain so easily
oh ok
They come in my short feed
Currently im doing PnC, any good book for that
and for beyond ioqm i suggest egmo and otis excerpts by evan chen
I have EGMO
but it bashed me
before i could Bash it
yea i saw a aops user say once "only bash if you are prepared to be bashed"
oh and art of problem solving is also a very good website
I did the "100" Geometry Problem section
out of the total 100 i could only solve 10
😭
its completly normal
do you guys actually buy the books or use a pdf or something??
Pdf, and xerox
who buys books?
ok thanks
I have that one
Yeah 2012 and 2013(first few problems) were bearable
is that one by rushil mathur?
oo
but only for inmo or higher
yes
oh, how are the problems
completly "hagh diya"
So, uh When did u start
7th grade
hey i want to cheer you up so see isi ugb 2025
hmm, ok
ye, maybe..
and the rest three are calculus
eyy the binomial coefficient ones can be solved by me
its the third one actually
problem 3 is binomial right?
7th is a one liner. You use the property that the orthic triangle of a triangle has its incenter O
oh wait nvm i was seeing UGA 🤣
oh haha
If I was planning to score high (at least 65/80) on the COMC (Canadian Open Math Competition) and the next stage of the competition (CMO, Canadian Math Olympiad), what types of resources would be appropriate from now until the COMC on October 30 this year (currently in Grade 10 so I might have to wait until COMC 2026 instead of 2025 to have more time to improve)? I’m currently working through AoPS v1 and v2 but not sure what other resources to use. Also tried Alcumus in the past but didn’t really jive with it. Ty in advance!
CMO? Impossible
Focus on score in the top 25% of Euclid or COMC first
For resources u can use like the Element by Euclid
Very helpful
If there are many geometric questions in the context
Element? Sorry not very familiar with other works in general
The author is Euclid
Just search The Element by Euclid
Very useful
Would qualification for the CMO be out of the question? I see that it's unrealistic to aim to suddenly improve to become high-ranking in the CMO, but at the very least qualifying for CMO I think is possible.
Maybe idk
Alright well after I finish the aops books ill check out your suggestion. Ty for your help!
Np
Oh yeah how was the v1 and v2 book in aops
Is it useful ?
well I had recently started the v1 so I can't say too much
Oh
but so far im learning new things so i would say look at the table of contents and see if anything is of interest
Good
In recent years those contests are just like stupid and boring for me, cuz so many people cheated
My friend brought the contest online and he just needs to memorize those answers and steps
He got in lol
can any1 help me prep of ioqm and rmo?
yes maybe i can
I am not sure about that, math changed a little bit, just a little bit from more than 2000 years ago to now
Mainly olympiad math
sure elements is a foundational text for the field of Euclidean geometry but it’s absolutely not well suited for a modern audience
unironically recommending it to learn geometry is a terrible idea
there are plenty of modern treatments that present the material in a more accessible format; once your basics are solid I’d recommend Evan Chen’s EGMO
AHAHAHA there's no way someone actually recommended Elements by Euclid unironically for maths competitions in the 21st century
honestly grind through as many past papers as possible
Hi!
there's not really some magic bullet you can use to like instantly get better, the way all the olympiad top scorers get good is just by doing an insane amount of past papers
Just a 2000 year old text
AOPS has a very large collection of past papers for various olympiads and competitions, which can be helpful if you've done all the past papers for the competition ur grinding for
as for books, lemme quickly check what level COMC is like quickly
right i'd say probably with a maths competition like that, you don't really need to focus on books & learning theory, it's probably better just to do problems
for olympiads evan chen's OTIS excerpts and EGMO are really useful
hi!
Alright, tysm for the advice!
also btw check out MODS, it's here
MODS is more suited for competition maths, so ur overall gonna get better advice lol
Have u read the book? lol I find it rlly helpful for me
Morden maths competition ( not maths Olympiad ) are not rigorous. Do u know why Chinese can get that much gold medals? Because they have a rigorous proof for everything. Teacher even use those books in class
...
they are not studying from elements by euclid
also you seem to...not understand what rigorous means if u think what the ancient greeks did was somehow more rigorous than what we teach nowadays
china can get that many gold medals because they care about olympiads in general and have a large population, nothing to do with how rigorous they teach X vs how they teach X in other countries
i'd say it's the fact that they do more problem solving that makes them better at maths
also elrichardo already explained why recommending elements is a bad idea
Do u think practice more problems will help u get in to Olympiad maths? Lmao
It’s a stage for geniuses not for hard working Dube
Only a large population? What about India ? They are smarter than other people cuz they have a rigorous maths background and education system better than other countries
Elements by Euclid is genuinely wild
That is just my own opinion cuz I found it helpful. I used some theorems in COMC.
recommending it for competitive math is so what
it's not particularly suited for modern math olympiads
Are u in IMO or something
sure, it's a very formal and down to the nitty gritty stuff, but not suited for actual problems
Not in it but I've solved my share of problems. Got into it too late
Oh
Well good advice might be just give up lol
Focus on calculus
but yeah like in practice you don't need such detailed and elementary math
You can’t beat those Chinese anyway
I mean, competitive math isn't just about winning competitions. It's about doing math because it's fun :p
Imagine your opponent is Gauss
although calc is also cool
Fun?
Only fun for geniuses
Stressful for normal people
I mean, firstly, I wouldn't say it's a divide between "geniuses" and "normal people". Anyone can get into it, and it's suited for all levels. And yeah, it's fun and rewarding
It’s so easy to score a 100%on those contests except Olympiad
Those contests are literally selling online
I don't see how that's related but ok
Not anyone
Only someone
yeah, anyone
with some amount of preparation anyone can solve idk a modular arithmetic problem
and then try out a diophantine
and then maybe move on to something involving cyclotomic
and so on
it's a progression, you don't have to start by solving IMO P6s
almost made the team for my country
but i have friends that made IMO
and i don't think they'd recommend reading elements for that either lol
that's the wrong attitude to have
sure it can look like the top imoers are just geniuses but like you don't see the amount of effort and problems they practise
mhm
they also have a large population tf
?
We all know they have a large population but did they do rlly well in IMO? Compared to China
well the top students are too busy trying to crack JEE
in China, if you do well in the IMO, you can get guaranteed admission to a top college
to my knowledge that doesn't really happen in India
IIT Kanpur and a few other places
plus its a cultural thing in china
well by now it's also a cultural thing in India
they put a lot of pressure on kids to excel in everything which isnt really healthy at all
but yes it's normal for primary school kids to go to maths olympiad training in China
STEM is seen as prestigious and yeah
Yep so China is better is not only about their culture
of course there are a million countries with intense study culture
not all of them care about IMO
Also their education
Yeah
Maybe idk
I wouldn't say China's education itself is really excellent, or at least it isn't usually regarded as such. It's more the use and abuse of excessive studying and pressure on children
well not really
there aint even a million countries
Education for maths
it's hyperbole
it's just as braindead as Indian education, trust me
search up 'gaofen dineng'
high test scores, low ability at life
all Western countries in general
they don't
Rlly?
the only one who does rlly
yeah
they do care, but in a different way. Not as in a requirement, but more as a fun activity
Seriously?
most other ivies dont
I mean out of all of those MIT does see the most value in IMO
but that's a vanishingly small number of people anyways
like yes it looks good but it wont make or break your app probably
it's not like they can survive based on IMO participants alone
a good essay and a passion project are prolly better
Cure cancer 🤓🤓🤓🤓
there's a million other things that you could do that would be just as worthwhile to unis
ye
and no it's not just research and comps
the main thing ig would be showing dedication
Plus daddy donate a building
School too easy and jump to maths Olympiad directly? lol😭
honestly inflation for getting into unis has gotten crazy
but yes it's talking about the inflation in unis
all inflation has gotten crazy :p
The question in IMO in the future will be prove Rieman’s hypothesis
doubt
arent u that mf i argued with before, that the chinese are somehow better at math than the others
that's like saying FLT would be in IMO, just not sensible
Bruh what ?
Do I know u ?
they did comment about China being very good at IMO in this convo but dunno
What did they say
Chill don’t swear
found it
I forgot
China is by no means unique
Let me check
In a way, they are, just not in a good way
Is it too hard for you guys to admit that China has better education in maths than other countries?
at least in this sense
I'm literally Chinese what are you talking about
thats crazy ahaaaahaha
it just isn't really that way, nor is it known for that
They teach u guys calculus in grade 10 right?
but yes that work mentality filters down everywhere in society
im literally chinese brah (although only ethnically)
it's known for its oppressive education
China isn't in the OECD so you have to trust government statistics
but even if people work the government-stated number, that would still be one of the highest working hours in the world
Their education is like stressful ig but under that certain conditions gifted people born
I mean it in the specific case of math education, and without offense to anyone
it also hinders a lot of gifted students
gifted underachievers for example
gifted people aren't born like that, plus gifted people underperform long term. It's not good
that person who seems like the class clown could be acting dumb all the time
cause they're afraid of all the extra tuition, pressure, and expectations if they were to be in the gifted class
Probably change that to “people that can bear pressure “
Ok
sigh
its jsut a term made up for parents to feel better about their child
they do
ok
that's a position borne out of pure ignorance
even if they do
the earth is flat ah
why bother using any term that is comparative
giftedness is not just eye-cue
it's like why do we bother using the term ADHD
so that kids can receive better learning opportunities and accommodations
sure, that's more like it. But it's in detriment of everyone else
gifted is not a neurodevelopmental disorder ❤️
Maybe
catering for the gifted means we can also cater for people with learning disabilities, neurodivergences, and those who are falling behind
it's part of neurodivergence
I'd say some people have ease for some things, and that's what's meant by it. It's just that long term they stop because of less effort and such
also there's a lot of gifted people who are also autistic and so on
just cause you have a higher 'natural ability' doesn't mean you'll automatically succed in life
if only it were that easy
At least they are geniuses in some categories💀
As long as u have achievements, u have to care about your personal life?
whats the point of those achievements if you arent well rounded and happy
"Giftedness" isn’t a real clinical or diagnostic category — unlike autism or ADHD, which have identifiable genetic markers and diagnostic criteria. Second, Intelligence is influenced more by environment than genetics, especially in childhood. Third, the term "gifted" is often used because people want to believe their child is special or smarter, and sometimes to avoid labeling a child as neurodivergent due to stigma. Finally, the label "gifted" is comparative and subjective, and can be socially isolating or misleading, rather than materially helpful.
okay I don't want to argue with you on this, except the fact that just cause a label can be misused, doesn't mean we should get rid of the label altogether
??? We don't use the r-word anymore for a reason yk
I never said anything close to the r-word
It's a response to "just cause a label can be misused, doesn't mean we should get rid of the label altogether"
well the reason why no one should use the r-word is that people mean something hateful when they use it
So you argue that no one should use the r-word beacuse they have malicious/bad intent, correct? If so, consider the fact that saying someone is "gifted" is just a euphemistic way of saying "smarter than everyone else".
What r word
that's not what gifted means
And if you wanna make a point about how it can be used as a complement
let me show you the columbus group definition
huh
“Giftedness is asynchronous development in which advanced cognitive abilities and heightened intensity combine to create inner experiences and awareness that are qualitatively different from the norm. This asynchrony increases with higher intellectual capacity. The uniqueness of the gifted renders them particularly vulnerable and requires modifications in parenting, teaching and counseling in order for them to develop optimally.”
Make what you want out of it, I just don't think that the label gifted is necessary and/or important
I can and I will, even using your definition, at the end of the day, it still counts as a comparative term
I never said giftedness was absolute
or that it was innate
the fact that it is innate or not is also irrelevant
Can we use the term like prodigy ?
eh of course it's a very touchy subject
I'd say labelling kids as prodigies is unhelpful
cause it implies that they'll be nothing if they don't become brilliant adults
It just alienates them socially, similar to the arguments I made about labels like gifted, etc.
Rlly?
it's so dumb how psychologists and clinicians thought of ADHD and autism as only a kid thing
from my experience, yes
That happened on adults too
yes, now adults are getting diagnosed which is great!
lol
I also think that calling kids prodigy will put immense pressure on them
it's also very dehumanising
you're not seeing the actual human or their personality
Yeah but no choices
you're just seeing: oh they're smart! they're not normal!
agreed
Depends on person perhaps
there's what academics mean when they say 'gifted' (and there's so many different views even in the academic community)
Says someone is a child prodigy
and then there's all the ways the label gets interpreted by society
a huge difference
Who know how to do calculus at age of 9 (I’m just postulating )
Or smth
Someone may love the label but some might feel pressured
I think if they love the label, they're in for a hard reality check
If they don't, great, that means they have self awareness, which is the first step into recognizing any problem
Recognising realistic social problems?
Well, thats one of them. 😭
Mental problems. Self- consciousness problems. The connection between the society and the world problems?
3 major categories of problems
Does anyone know some good questions about aithmetic functions (like d(n), sum of divisors, mobius function, dirichlet convolution). IMO/USAMO level
imo wasn't as big of a thing in india a few years ago cus it wasn't that well-known, but now that it's becoming a bigger thing more ppl r doing it & they're doing quite well now
can anyone help in preparaion for IOQM
i mean everyone else has commented that this just isn't true
and also even if we are looking at it statswise that they perform better at IMO than say other countries, if we adjust for population wouldn't that suggest US has a better education than china?
What
I dont know what u mean
anyone? pls
i have a teacher but i wanted someone that can discuss questions and help me out a bit
Then just post in this channel
alr ty 😄
guys how can i practice comp math there is a site or some thing
then go to resources and then to alcumus or the community tab
someone please break down this question
its for a computing competition that i did in the past but it involves summations
the solutions are uploaded but it looks like a PhD thesis
Sorry its a bit of a strain to read it
Do you mind taking a screenshot from your computer instead? Or even just sending the file if its possible?
wrong server
this channel is for maths competitions cause this is the maths server
Hey ,
I got a JEE Advanced Question
Can you solve it
!da2a
No need to ask “Can I ask…?” or “Does anyone know about…?”—it’s faster for everyone if you just ask your question! See https://dontasktoask.com/
Let f(x)=∫₀ˣ t³/(t⁴+1) dt and f⁻¹ denote the inverse function of f. Find (f⁻¹)'(π/8).