Solving a 'Stanford' University entrance exam | a=?

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  • Опубліковано 1 січ 2025

КОМЕНТАРІ • 18

  • @fadetoblah2883
    @fadetoblah2883 3 дні тому +1

    If you posit right from the start that x=2ᵃ, the initial equation can immediately be rewritten as x + 1/x = 4, and then as x² - 4x + 1 = 0. This feels more natural (at least to me) than multiplying both sides by 2ᵃ and using the substitution afterwards. In any event, nice little problem, very well explained.

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  3 дні тому

      nice dear

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  3 дні тому

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  • @xavierplatiau4635
    @xavierplatiau4635 3 дні тому +1

    This can be rewritten as cosh(a*ln(2)) = 2 and so a = +-arcosh (2)/ln(2)
    On [1 , oo[ arcosh is ln(x + sqrt (x^2 - 1))
    So a = +-ln(2 + sqrt(3))/ln(2)

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  3 дні тому

      nice job, thanks

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  3 дні тому

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  • @ManojkantSamal
    @ManojkantSamal 3 дні тому

    ^=read as to the power
    *=read as square root
    a={log(2+*3)}/log2
    Or
    a= {log(2-*3)/log2......May be

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  3 дні тому

      okay dear

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  3 дні тому

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  • @JPTaquari
    @JPTaquari 6 годин тому

    My way, a = 1,9
    1) 2^a + 1/2^a = 4
    2) trick, 2^a = Y
    3) Y² - 4Y + 1 = zero
    By baskara ou Google, Y' = 3,7321 ; Y" = 0,2679 ( I will use the first, but...)
    4) 2^a = 3,7321
    a = 1,9 ( using my cell calculater )
    Prove: 3,7321 + 1 / 3,7321 = 4
    4 = 4
    Bingo from Brazil !!!!!!

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  3 години тому

      beautiful way

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  3 години тому

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  • @jacksdu13
    @jacksdu13 3 дні тому

    Didn't see the video. No paper
    Result is ln(2+√3)/ln(2).
    Replace 2^a=x; x +1/x=4
    x^2 +1 = 4x ; x^2 - 4x -1 =0
    Complete squares
    (x+2)^2 -3 = 0
    x= 2 + √3
    a= ln (2+√3)/ln(2)

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  3 дні тому

      thanks for solution

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  3 дні тому

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  • @firebuble
    @firebuble 2 дні тому

    Too many innecessary steps 😢

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  День тому

      only explanation to clear concepts

    • @AsadInternationalAcademy
      @AsadInternationalAcademy  День тому

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