Math Olympiad Question - Can You Spot the Trick?

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  • čas přidán 30. 12. 2023
  • Diving into some of the most beautiful Mathematic Olympiad Problems ever set! In today's video, we look at a problem from INMO 1993 which uses geometry!
    Apologies for not showing my face in this video! I came down with the flu and looked rather ill!
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    For those of you that are new here, hi there 🌞 my name is Ellie and I'm a Cambridge Part III Mathematics Graduate and current Astrodynamics Software Engineer! This channel is where I nerd out about maths, physics, space and coding so if that sounds like something you're interested in, click the subscribe button to follow along ☺️
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Komentáře • 79

  • @siddhantjain490
    @siddhantjain490 Před 6 měsíci +14

    Geometrical proves are so complex yet beautiful.

  • @stringtheory5892
    @stringtheory5892 Před 6 měsíci +17

    Really enjoyed the whole explanation! Keep it up!

    • @EllieSleightholm
      @EllieSleightholm  Před 6 měsíci +3

      Thank you so much!☺️

    • @stringtheory5892
      @stringtheory5892 Před 6 měsíci +2

      Can you please try to make a video on William Lowell Putnam Maths competition. Some of those questions are really interesting!

    • @EllieSleightholm
      @EllieSleightholm  Před 6 měsíci +3

      Yes definitely!!

    • @leif1075
      @leif1075 Před 6 měsíci

      ​@EllieSleightholm Can you do some AIME questions also..and hope you cam respond to my other question when you can. Thanks very much.

  • @techcraft455
    @techcraft455 Před 6 měsíci +1

    Very beautiful solution! I first thought of involving complex numbers but this is much more elegant and easy to explain.

  • @sourabhsoni2930
    @sourabhsoni2930 Před 6 měsíci +1

    Happy new year Ellie🎉😊❤

  • @sci-star5085
    @sci-star5085 Před 6 měsíci +1

    It’s really wow how I end up saying wow after every video of you
    That’s not commonly happening with mathematics content
    Great work 👏🏻✨✨✨

  • @teamomine
    @teamomine Před 6 měsíci

    i don’t like math but i feel the joy ot gives when someone solves questions… your video give me some little motivation ❤

  • @OmarWehbeh-hXO
    @OmarWehbeh-hXO Před 6 měsíci +1

    This is one of the most beautiful Mathematical proves Ive yet to see, good job to the ppl who got it in the IMO.

  • @physicsanimated1623
    @physicsanimated1623 Před 6 měsíci

    This is like such a cute video! I was waiting on my Neural Network to finish training and watched this refreshing video! 😇

  • @armanavagyan1876
    @armanavagyan1876 Před 6 měsíci +3

    Please keep more problems like THIS comming up👍

    • @EllieSleightholm
      @EllieSleightholm  Před 6 měsíci +3

      You got it!

    • @leif1075
      @leif1075 Před 6 měsíci

      ​@@EllieSleightholmWhy did tou gloss over the important step.of HOW you deduce each of the angles is 120 since if you don't know what you said by memory you didn't show how to deduce the angle size.

  • @jamesjohn2537
    @jamesjohn2537 Před 6 měsíci +1

    Ellie, happy new year to you! I enjoyed your explanation, And am wondering where else can, I follow you, you re likely active than this platform?? And thanks

  • @ndeleonn
    @ndeleonn Před 6 měsíci +1

    One word: Beautiful!

  • @adoptmeeverything
    @adoptmeeverything Před 6 měsíci

    Such an elegant proof.

  • @diogomorel2226
    @diogomorel2226 Před 6 měsíci

    hello! happy new year!! all the best.. greetings from Brazil

  • @Arya56737
    @Arya56737 Před 6 měsíci +3

    Hey you got new sub today
    By the way, nice explanation!

  • @markfullbrighton5070
    @markfullbrighton5070 Před 6 měsíci +1

    I was wondering if you would react to an exam from Math 55 at Harvard. It's supposed to be one of the most difficult undergraduate math classes in the USA.

  • @s.v.discussion8665
    @s.v.discussion8665 Před 6 měsíci

    Do you use notability for note taking?

  • @armanavagyan1876
    @armanavagyan1876 Před 6 měsíci +3

    I am UR biggest fan🤗

  • @user-nf4iz1jv1p
    @user-nf4iz1jv1p Před 6 měsíci +1

    Hey elli 😊

  • @michaelaristidou2605
    @michaelaristidou2605 Před 4 měsíci

    What do u use to write/type?

  • @Professional-Hater
    @Professional-Hater Před 6 měsíci

    Hey Ellie! If you want to, then take a look at ISI UGA and UGB Exam, it's for highschool students in India and has better question in the UGB section compared to JEE Advanced, It'd be interesting to hear your thoughts on it!

  • @fahrenheit2101
    @fahrenheit2101 Před 6 měsíci

    Ah you seem to have done otherwise - I'll be sure to check out the method soon

  • @ListentoGallegos
    @ListentoGallegos Před 6 měsíci

    The picture threw me off for a second. I was like," Hey why does b look greater than x-a-b!?"

  • @madhavchaturvedi-ov7km
    @madhavchaturvedi-ov7km Před 6 měsíci +1

    ellie good evenung ....as a maths lover i also want to be a mathematician like you ...and be cambridge graduate ..can you plzz make a video how you enterd cambridge means which exam we have to clear to be a student at cambridge, and what are the fees structure thereplzzzzzzzzzzzzzz didi

  • @md2perpe
    @md2perpe Před 6 měsíci

    Can this hexagon be constructed from equilateral triangles with side 1?

    • @Tommy_007
      @Tommy_007 Před 6 měsíci

      Yes. You can even (rather easily) find the hexagon by tiling the plane using such triangles.

  • @sourabhsoni1114
    @sourabhsoni1114 Před 6 měsíci +4

    I have some questions, can you please tell me, there are some question which i want to ask can you tell me how can i send it to you.

  • @Yagyesh12345
    @Yagyesh12345 Před 6 měsíci +1

    Hallo Ellie mam! Describe your journey to Cambridge
    I hope ❤

  • @airbornpigz
    @airbornpigz Před 6 měsíci

    Another solution at 9:22 is {a=1, b=3, c=5, x=10}. As far as I can tell this is the only other solution (up to permutations of a,b,c)

  • @dugong369
    @dugong369 Před 6 měsíci

    a=1, b=3, c=5, and x=10. I did it a more random way and got a different answer. The triangle method is very elegant, and reassured me my result was valid.

  • @arpittttt
    @arpittttt Před 6 měsíci

    Did it myself by same method , really proud of myself love from india

  • @lywzcx663
    @lywzcx663 Před 6 měsíci

    I used a different solution. Considering six sides as a to f. Since all angles are equal so 120 degrees, ad, be and cf must be parallel, which means a+b=d+e, b+c=e+f and c+d=a+f, combine this and the 123456 and the question is solved.

  • @vanshvyas4149
    @vanshvyas4149 Před 6 měsíci

    This could even have been done considering every side as a complex number with exponent angle being multiple of 60 and adding all of them to get zero.

  • @itsinvalid07
    @itsinvalid07 Před 6 měsíci +1

    Preparing for jee but i do not have much intrest in Maths .

  • @Amankumar-ku5wp
    @Amankumar-ku5wp Před 6 měsíci

    Can you plz solve jee advanced paper 2023?...

  • @gavintillman1884
    @gavintillman1884 Před 6 měsíci

    Is the word “convex” needed? I’d have thought “all angles equal” implied “all angles 120°” and hence convex.

    • @peterpankert3810
      @peterpankert3810 Před 6 měsíci

      That's true because the sum of all interior angles must be 720° in both cases, convex and concave. So every angle must be 120°.

  • @sourabhsoni2930
    @sourabhsoni2930 Před 6 měsíci +3

    Hello, Ellie in mathematics there are some topic which doesn't feel. Please tell me how can I take the feel of that topic 😊

    • @EllieSleightholm
      @EllieSleightholm  Před 6 měsíci +5

      Hey there, I'm not quite sure what you mean, could you elaborate please? ☺️

    • @sourabhsoni2930
      @sourabhsoni2930 Před 6 měsíci +4

      ​@@EllieSleightholm There are some topics which are not understood easily. How can I understand that one very easily

    • @EllieSleightholm
      @EllieSleightholm  Před 6 měsíci +4

      @@sourabhsoni2930 i think finding out what type of learner you are helps massively. If you're a visual learner then try find youtube videos explaining certain concepts. if you prefer reading, then try find books on similar topics. For me, if i was learning a difficult topic I would break it down into the prerequisite topics and make sure I truly understood them before moving on! It's all about building a base foundation and building from there!

    • @sourabhsoni2930
      @sourabhsoni2930 Před 6 měsíci +3

      @@EllieSleightholm thank you so much Ellie 😊

    • @leif1075
      @leif1075 Před 6 měsíci

      ​@@EllieSleightholmwhat if you don't think k of the trick..can't youndolve.snotjer wah? I thought of making a swuare or recession gle around the hexagon..surely this would work also just mauve be a bit more complex? Mauve breaking the recession gle then I to triangles mauve..not sure if inwpjldve..hope you can dare feedback..

  • @YogendraSingh-ir6dh
    @YogendraSingh-ir6dh Před 6 měsíci

    Please tell me whether I should take a laptop or a tablet for studies.

    • @Tommy_007
      @Tommy_007 Před 6 měsíci +1

      Only use paper and pen if you really want to learn mathematics!

  • @user-je8mn8vt3r
    @user-je8mn8vt3r Před 6 měsíci +1

    Please mam or didi teach me olympiad AMC or ioqm i am from India. Top or hardest questions topics on geometry, algorithm,etc. I read this time and like blackpenredpen channel one short videos topic wise or etc.reasons

    • @user-je8mn8vt3r
      @user-je8mn8vt3r Před 6 měsíci +1

      And board in front read so face emotions read because my English language some weakness😊😊😊

    • @user-je8mn8vt3r
      @user-je8mn8vt3r Před 6 měsíci

      And Didi or mam tibees from read no reasons

  • @diogomorel2226
    @diogomorel2226 Před 6 měsíci

    oh! you should to see the problems from the exam called ''ITA and IME''. They are military exams from Brazil and really hard! But.. its funny. Physics from ITA... wow.. so hard.

  • @beancount811
    @beancount811 Před 6 měsíci

    Could you get slightly sneaky with combinatorics and counting here instead?
    Say, tessellate the plane with equilateral triangles and pick 6 around a vertex. Then, since the pattern is infinitely repeating, you just need to get crafty with permuting {1...6} for your edge labelling throughout the tessellation to match the question spec. Presto! A slightly troll answer which probably would get no points, but inside you'd burn with a passion of a thousand suns!🌞🕶😎

    • @Tommy_007
      @Tommy_007 Před 6 měsíci +1

      I did the same. This solution should get maximum points if explained properly.

  • @arzaenglishsubtitles8041
    @arzaenglishsubtitles8041 Před 6 měsíci

    Nice, but I believe that Olympiad problems have changed over time, since this one is kind of an old one. To show what olympiad questions look nowadays it would be better to take a problem from past IMO(International Math Olympiad) questions.

  • @Yagyesh12345
    @Yagyesh12345 Před 6 měsíci +1

    Hay Ellie mam ❤🎉🎉

  • @farshidyazdaani9021
    @farshidyazdaani9021 Před 5 měsíci

    ❤👍

  • @danksourav
    @danksourav Před 6 měsíci +4

    Hey Ellie today it's my birthday

  • @luciafrancoalvarez
    @luciafrancoalvarez Před 6 měsíci +1

    Why is x equal to 9?

  • @MebuneDonstand
    @MebuneDonstand Před 6 měsíci

    Hey your really a great person I admire the way you go about the maths word I have my personal question I will like to ask you if you don't mind

  • @lauracracogna4814
    @lauracracogna4814 Před 6 měsíci +1

    why x=9?

    • @EllieSleightholm
      @EllieSleightholm  Před 6 měsíci +3

      x must equal 9 for the sides of the hexagon to match the values in the question. i.e. each side of the large equilateral triangle will have sides:
      1 + 6 + 2 = 9,
      1 + 5 + 3 = 9,
      2 + 4 + 3 = 9.
      Hope that helps!

    • @lauracracogna4814
      @lauracracogna4814 Před 6 měsíci

      @@EllieSleightholm thank you

    • @Tommy_007
      @Tommy_007 Před 6 měsíci

      As someone pointed out in another comment, {a=1, b=3, c=5, x=10} is also possible.

    • @dano6187
      @dano6187 Před 6 měsíci

      @@EllieSleightholm 9 is the smallest possible value for x. The side with length 6 must be in one of the sets and adding the shortest side lengths of 1 and 2 totals 9. It is easy then to see that {1,6,2,4,3,5} is the only valid permutation for x=9 excluding rotations and reflection. This permutation when rotated is also the solution for x=12 which is the largest possible value for x.
      The only side length combinations that would work for x=10 are 1+3+6,1+4+5 and 2+3+5. Only 1, 3 and 5 are repeated so these must be the vertices and thus {1,6,3,2,5,4} is the only solution for x=10 and x=11.
      There can be no other solutions.

  • @valboolin3538
    @valboolin3538 Před 6 měsíci

    Клетки, клетки , клетки , как в метрополитене вагонетки

  • @fahrenheit2101
    @fahrenheit2101 Před 6 měsíci

    I actually worked it out. Isometric grid, then you can pick the obvious coordinate basis, from there it works out fairly easily.
    Wlog, start with 6 going right, then find some loop that takes you back where you started - "left" 6, and "up" 0. Each side travels along a nice line in the grid so that the coordinates change by integer amounts so you can get a couple equations if you want.

  • @drowranger8433
    @drowranger8433 Před 6 měsíci

    OMG you are smart & cute ^.^

  • @jeffsamuelson7221
    @jeffsamuelson7221 Před 6 měsíci +3

    Another solution: take the first side to be the interval [0,1] in the complex plane, and then we require that
    1+ Σa_k e^{ikπ/3}=0 where a_k are the numbers 2,3,4,5,6 in some order and k goes from 1 to 5. Then taking real and imaginary parts we get (2+a1-a2-2a3-a4+a5)=0 and (a1+a2-a4-a5)=0. Then subtracting these gives 1+a5=a2+a3. Adding the equations gives 1+a1=a3+a4. Set a3=2, then a5=a2+1 and a1=a4+1, so we can take a2=5,a5=6,a4=3,a1=4. So the sides ordered counterclockwise have lengths 1,4,5,2,3,6
    Also nice video!

  • @hemlyns9916
    @hemlyns9916 Před 6 měsíci

    The phrase "in some order" is redundant - the sides could not be in no order.

    • @Tommy_007
      @Tommy_007 Před 6 měsíci

      No, the phrase means that any order is acceptable.

    • @hemlyns9916
      @hemlyns9916 Před 6 měsíci

      No. There is no suggestion in 1,2,3,4,5,6 that a given side has to be adjacent to a given other side.@@Tommy_007

  • @user-si2lz2vx8f
    @user-si2lz2vx8f Před 5 měsíci

    Learn my student time 😂,my mother teaches me