How to Think Outside the Box? | Nice Algebra problem | (Math Olympiad Preparation)

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  • เผยแพร่เมื่อ 17 ม.ค. 2025

ความคิดเห็น • 81

  • @htunwynn7523
    @htunwynn7523 ปีที่แล้ว +19

    Very nice solving.

    • @PreMath
      @PreMath  ปีที่แล้ว +2

      Thank you! Cheers!

  • @XLatMaths
    @XLatMaths ปีที่แล้ว +20

    I used complex numbers. Solving using QF, x = √3/2 ± i/2 which is e^±iπ/6 in its principal form, so x¹⁰⁰⁰ = e^500iπ/3. 500 is congruent to 2 (mod 6) so x¹⁰⁰⁰ is e^2iπ/3.
    X¹⁰⁰⁰ + 1/x¹⁰⁰⁰ is therefore 2cos(2π/3) which is -1.

    • @almosawymehdi3416
      @almosawymehdi3416 ปีที่แล้ว +5

      I did the same way, two minutes to solve this problem

    • @talhahaque-sq2bc
      @talhahaque-sq2bc ปีที่แล้ว

      another answer of this question is -2

  • @jamesharmon4994
    @jamesharmon4994 ปีที่แล้ว +8

    The way I would have attacked this is multiplying the given statement through with "x". This then results in x^2 + 1 = sqrt(3)x. Then, put everything on the left hand side gives x^2 - sqrt(3)x + 1 =0. Then use quadratic formula to find x. Then substitute that value into x^1000 and 1/x^1000.

    • @geyorge6573
      @geyorge6573 ปีที่แล้ว

      bro have u tried solving the quadratic theres no real solutions

    • @jamesharmon4994
      @jamesharmon4994 ปีที่แล้ว +2

      @@geyorge6573 so?? When you take them to even powers, it becomes real.

    • @rajbinani
      @rajbinani ปีที่แล้ว

      I took same approach and did it in a minute without pen and paper. What’s wrong with this approach?? Works very well imo. Not sure why such a complicated approach in the video though

  • @ravikrpranavam
    @ravikrpranavam ปีที่แล้ว

    Very well explained

  • @sunil.shegaonkar1
    @sunil.shegaonkar1 ปีที่แล้ว +2

    X^4 + 1/ X^4 = -1, and further squaring this expression does not change. Because 1000 is divisible by 4, the 1000 powered expression is also minus 1.

  • @mahinnazu5455
    @mahinnazu5455 ปีที่แล้ว +1

    Wow...thats great solution...
    Thank u my favourite Sir

  • @aminimam5118
    @aminimam5118 9 หลายเดือนก่อน +2

    Just square both sides X+1/x = sqrt (3). You get x2+1/x2 =1. Square again, you get x4+1/x4=-1. Square again, you get X8+1/x8=-1. No matter how many times you square, the answer will be -1. Since 1000 is an even number, the answer is -1.

    • @cosmolbfu67
      @cosmolbfu67 8 หลายเดือนก่อน

      Yes but if equation is x^998 + 1/x^998 =?
      solution = 0

  • @bigm383
    @bigm383 ปีที่แล้ว +2

    Fabulous, thanks Professor!❤

  • @manojkantsamal4945
    @manojkantsamal4945 ปีที่แล้ว

    Respected sir, You are one of the best

  • @hichamitani6433
    @hichamitani6433 ปีที่แล้ว

    Amazing problem and solution
    Superb

  • @KAvi_YA666
    @KAvi_YA666 ปีที่แล้ว

    Thanks for video.Good luck sir!!!!!!!!!

  • @advancedintention7169
    @advancedintention7169 ปีที่แล้ว +1

    Thank you very much sir......

  • @henrbenbrown
    @henrbenbrown ปีที่แล้ว

    Fabulous!...thank you so much!!

  • @mvrpatnaik9085
    @mvrpatnaik9085 ปีที่แล้ว

    Nice Explanation

  • @dirklutz2818
    @dirklutz2818 ปีที่แล้ว +2

    Tremendous!

  • @alexgorman4864
    @alexgorman4864 10 หลายเดือนก่อน

    There is another way of doing it.. when you solve for x in the initial equation you can find that x= cost + isint , where t= 60 deg. then using De moiver's theorem x^1000 = cos(1000t) + isin(1000t) and 1/x= cost-isint so 1/(x^1000) = cos(1000t)-isin(1000t) . Hence sin terms cancelled and finally it becomes 2cos(1000t) =-1

  • @alster724
    @alster724 ปีที่แล้ว

    Nice solution

  • @vcvartak7111
    @vcvartak7111 ปีที่แล้ว

    It's good you are also talking algebraic problems

  • @paulortega5317
    @paulortega5317 ปีที่แล้ว +1

    As you increment the exponent, the values repeat after 12 terms. 1000 module 12 = 4. The 4th value in the series is -1.

  • @md.shahadathossen5738
    @md.shahadathossen5738 ปีที่แล้ว

    That's cool !

  • @lavoiedereussite922
    @lavoiedereussite922 ปีที่แล้ว

    Thank

  • @walidbinsiddik
    @walidbinsiddik ปีที่แล้ว +3

    Yeah afcource i should know 6*167=1002

  • @talhahaque-sq2bc
    @talhahaque-sq2bc ปีที่แล้ว

    Is the alternative answer (-2)

  • @Copernicusfreud
    @Copernicusfreud ปีที่แล้ว +2

    I came up with the answer another way. If I did something wrong, please feel free to address it and provide a correct solution. Thanks. I worked with the first equation of (x + 1/x) = sq rt(3). I squared both sides and ended up with x^2 + 1/x^2 = 1. I took this equation and squared both sides and ended up with x^4 + 1/x^4 = -1. I took this equation and squared both sided and ended up with x^8 + 1/x^8 = -1. The pattern should repeat until reaching x^1000 + 1/x^1000, resulting in -1 as the answer. So, the answer is -1.

    • @Duke_Of_Havoc
      @Duke_Of_Havoc ปีที่แล้ว +5

      Except this pattern won't reach 1000 since 1000 isn't a pure multiple of 2. The pattern you are following is 2,4,8,16,32,64 and so on. It won't reach 1000 as you can see.

  • @kalpanadeka8226
    @kalpanadeka8226 ปีที่แล้ว +1

    I solved it in my mind 😊

  • @Roberto74B
    @Roberto74B ปีที่แล้ว +1

    i did to consider 1/x as X/X^2 ... so X^3+X=X^2*sqrt_2(3) ..... next x^6+x^2+2x^4 = 3x^4 .... next x^6-x^4+x^2= 0 .... put Y=X^2 ... come out y^3-Y^2+1=0 ... one real solution and two immaginary solutions ... and at the end i did consider Y^500 + Y^-500 = ...... but the result don't is not the same
    i did to be a bit not convinced about to have, you, to arrive to define x^1000=-1/x^2 before you did flip the equation ... and next of the flip (nominator with the denominator) you have used the previous x^1000=-1/x^2 to continue on resolving ... maybe it's super correct ... but maybe no? ... you are a really super professor, my compliments, but in my mind there is something that retain it a remote not possible right logic ...
    have a nice day

  • @राजनगोंगल
    @राजनगोंगल ปีที่แล้ว

    👍👍👍👍👍👍

  • @NITINCHAUHA62
    @NITINCHAUHA62 ปีที่แล้ว +1

    Sir make a video on Mathematics facts for us ❤please🙏🙏 ..... In addition I like u ❤❤❤

  • @IlyaNickkhah-bz1ii
    @IlyaNickkhah-bz1ii ปีที่แล้ว

    How x to the power of an even number (2k = 6) is equal to a negative number ( -1) ? X^6 is not equal to -1 or I have neglected sth and made a mistake so please correct me if I'm wrong

  • @richardlollar7751
    @richardlollar7751 ปีที่แล้ว

    X to the 6th equals a negative one? Are we including complex numbers?

    • @RickDesper-v8z
      @RickDesper-v8z ปีที่แล้ว +1

      For x > 0, (x + 1/x) >= 2. So you have to include complex numbers.

    • @JamesDavy2009
      @JamesDavy2009 ปีที่แล้ว +1

      In short, yes. Even so, with up to six complex roots that x could equal to, certain operations can yield real solutions such as i^2 = -1.

  • @BrendanAus
    @BrendanAus ปีที่แล้ว

    Why can't I save it?

  • @pralhadraochavan5179
    @pralhadraochavan5179 ปีที่แล้ว

    Good morning sir

  • @e65666
    @e65666 ปีที่แล้ว

    I was doing the right thing the first time then decided to brute force it

  • @webscreener8797
    @webscreener8797 ปีที่แล้ว +2

    x^6= -1 impossible?!?

    • @manojitmaity7893
      @manojitmaity7893 ปีที่แล้ว +3

      When x equals to i, x⁶ may be equal to -1.

    • @LogintoMaths
      @LogintoMaths ปีที่แล้ว +1

      Its complex number

  • @lk-wr2yn
    @lk-wr2yn ปีที่แล้ว

    Is that possible x^6= never negativ? So -1 as result is not possible?

    • @JamesDavy2009
      @JamesDavy2009 ปีที่แล้ว +2

      x^6 = -1 means that x equates to a complex number.

    • @lk-wr2yn
      @lk-wr2yn ปีที่แล้ว

      @@JamesDavy2009 Thanks, I never saw this in school...

    • @JamesDavy2009
      @JamesDavy2009 ปีที่แล้ว +1

      @@lk-wr2yn Complex numbers tend to be taught at the university level or upper-level high school if you're lucky.

    • @howareyou4400
      @howareyou4400 ปีที่แล้ว +2

      @@JamesDavy2009 Wait, there are regions in the world that does NOT teach complex number in high school?

    • @JamesDavy2009
      @JamesDavy2009 ปีที่แล้ว +1

      @@howareyou4400 Apparently. This was based on my experience. I did learn calculus and linear algebra in high school.

  • @j.c4007
    @j.c4007 ปีที่แล้ว +2

    😮 how x⁶ can be equal to : -1.
    Even x is an odd number , the result is not an odd number ?

  • @28.quachphuc26
    @28.quachphuc26 ปีที่แล้ว

    Is there any other possible answer: I got 1

  • @nantesloire
    @nantesloire ปีที่แล้ว

    x⁶ = -1 ???? and x +1/x =3½ never

  • @saumyaadhikari8078
    @saumyaadhikari8078 ปีที่แล้ว

    -1. Two minute job 😊😊

  • @sattkrit_pathak
    @sattkrit_pathak ปีที่แล้ว

    x^6 = -1 ? they dont usually give imaginary numbers in there exams

    • @rakeshprasad7313
      @rakeshprasad7313 ปีที่แล้ว

      It's not a imaginary no 😮

    • @RickDesper-v8z
      @RickDesper-v8z ปีที่แล้ว

      I think this presentation is intended to show that you can solve the problem only using basic algebra. But it takes a fairly long path to do so, and you have to pull ideas out of thin air.

  • @LogintoMaths
    @LogintoMaths ปีที่แล้ว

    I solved in 1 min

  • @Wahid7X
    @Wahid7X ปีที่แล้ว

    I solve this by a pattern

  • @utsabrajsarkar7776
    @utsabrajsarkar7776 ปีที่แล้ว +1

    Too much struggle for a trivial problem.
    x+1/x=√3 => x²+1=√3x => x²-√3x+1=0.
    It's a polynomial with real coefficients and discriminant 3-4 x=z=cos t+I sin t for some t. Now, x+1/x=√3 yields cos t=√3/2 => t=±π/6 so, x^1000+1/x^1000=2 cos (1000π/6) the rest is easy.

    • @matteogorghetto
      @matteogorghetto ปีที่แล้ว

      This is how i solved it. One thing though, The assumptions should have included that x can belong to the realm of complex numbers, usually, one assumes that x belongs to realm of REAL numbers, in which case there's no solution. Given details are not accurate on here.

  • @ploi4590
    @ploi4590 ปีที่แล้ว +1

    There is no such x!

    • @itzrealzun
      @itzrealzun ปีที่แล้ว +2

      No REAL x, but COMPLEX x exists

    • @ploi4590
      @ploi4590 ปีที่แล้ว

      If that is what you assume, then the answer can be found without using the algebra trick.@@itzrealzun

  • @mohammadmatinafshordidibaz9966
    @mohammadmatinafshordidibaz9966 ปีที่แล้ว

    X^6=-1 it's not true

    • @RickDesper-v8z
      @RickDesper-v8z ปีที่แล้ว

      It's not real. Which isn't the same thing. It's a non-real solution.

    • @JamesDavy2009
      @JamesDavy2009 ปีที่แล้ว

      The fundamental aspect of a complex number lies in the imaginary unit i (j to engineers) such that i^2 = -1. The Mandelbrot Set uses complex numbers to trace out its shape.

  • @lavoiedereussite922
    @lavoiedereussite922 ปีที่แล้ว

    Thank