Solving a 'Stanford' University entrance exam

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  • Опубліковано 29 гру 2024

КОМЕНТАРІ • 16

  • @nalbrt
    @nalbrt 8 днів тому +2

    Acredite se quiser, no brasil isso é ez pz, e eu sou um cara que mora numa zona muito rural, estudo em colegio público estadual, e achei isso relativamente fácil, quem dera se entrar na faculdade no Brasil fosse tão fácil assim... Mas amei a explicação, voce explicou muito bem, acho legal em ver indianos muito bons em matemática

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  8 днів тому +1

      Watch 110+ most important olympiad questions with solutions by just clicking on the link below
      ua-cam.com/play/PLybCHBiqtqWP-TrcsG21MXXxlknROi514.html
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    • @AsadInternationalAcademy
      @AsadInternationalAcademy  8 днів тому +2

      Yes, it's easy. thank you so much!

    • @nalbrt
      @nalbrt 6 днів тому

      @@AsadInternationalAcademy thank you so much

  • @jidehuyghe4051
    @jidehuyghe4051 8 днів тому

    Pas évident ! mais avec ténacité Bravo !!

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  8 днів тому

      Watch 110+ most important olympiad questions with solutions by just clicking on the link below
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    • @AsadInternationalAcademy
      @AsadInternationalAcademy  8 днів тому

      easy dear

  • @emanuele59b
    @emanuele59b 8 днів тому

    Simplify by sqrt(6) and the expression is R^12 where R = 2/(Sqrt(5)+1). One observes that R is the inverse of the golden ratio S. The golden ratio solves the equation S^2 -S - 1 = 0 so we can obtain recursively all the S powers by S^2 = S + 1 and we get S^n = Fib(n) * S + Fib( n-1) where Fib is the Fibonacci number. Now Fib(11) = 89 and Fib(12) = 144 so S^12 =
    89 + S * 144.
    Finally we get R^12 = 1 / S^12 = 1 / ( 89 + S * 144). Putting the expression of S inside we get R^12 = 1/ ( 161 + 72* Sqrt(5) ) and rationalizing we get R^12 = ( 161 - 72* Sqrt(5) ) / (161^2 - 72^2 * 5 ). The denominator is 25921-25920 = 1 so the result is = ( 161 - 72* Sqrt(5) ) .

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  8 днів тому +1

      Wonderful dear, thanks

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  8 днів тому +1

      Watch 110+ most important olympiad questions with solutions by just clicking on the link below
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  • @ellmg4733
    @ellmg4733 9 днів тому +2

    I didn't got the x^4... Why is x^4 = the problem from the beginn?

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  8 днів тому

      in fact this problem is x^12 but I reduced it to x^4 then solved finally

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  8 днів тому

      Watch 110+ most important olympiad questions with solutions by just clicking on the link below
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  • @walterwen2975
    @walterwen2975 8 днів тому

    A Stanford University entrance exam: [(√24)/(√30 + √6)]¹² =?
    (√24)/(√30 + √6) = (2√6)/[(√5 + 1)√6)] = 2/[(√5 + 1) = [2(√5 - 1)]/(5 - 1) = (√5 - 1)/2
    Let: a = (√5 - 1)/2, a² = [(√5 - 1)²]/2² = (5 - 2√5 + 1)/4 = [2 - (√5 - 1)]/2 = 1 - a
    a⁴ = (a²)² = (1 - a)² = 1 - 2a + a² = 1 - 2a + (1 - a) = 2 - 3a
    a⁶ = (a²)(a⁴) = (1 - a)(2 - 3a) = 2 - 5a + 3a² = 2 - 5a + 3(1 - a) = 5 - 8a
    a¹² = (a⁶)² = (5 - 8a)² = 25 - 80a + 64a² = 25 - 80a + 64(1 - a) = 89 - 144a
    [(√24)/(√30 + √6)]¹² = a¹² = 89 - 144a = 89 - 144[(√5 - 1)/2] = 161 - 72√5
    Final answer:
    [(√24)/(√30 + √6)]¹² = 161 - 72√5