Every nice maths olympiad algebra problem | Can you solve for a+b=? | Algebra

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  • Опубліковано 4 лис 2024
  • In this video, I'll be showing you step by step on how to solve this Olympiad Maths Exponential problem using a simple trick.
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КОМЕНТАРІ • 6

  • @damyankorena
    @damyankorena 2 місяці тому +3

    I am bored so lets solve with complex numbers.
    4+4i=a²+2abi-b²=(a+bi)²
    a+bi=√(4+4i)
    Let z=4+4i
    |z|=4√2
    z/|z|= 1/√2 + i/√2
    Arg(z)=π/4
    Therefore
    √z=2∜2 * e^(πi/8)
    Which as shown earlier is equal to a+bi.
    a=Re(√z), b=Im(√z)
    a=2∜2 * sin(π/8)
    b=2∜2 * cos(π/8)
    a+b=2∜2 * √2 sin(⅜π)
    a+b= 2^(¾) * √(2+√2)
    а+b=2√(1+√2)
    Naturally while taking the square root of z instead of
    Arg(√z)=⅛π we can use
    Arg(√z)=⅝π which will by similar methods turn out to be the other solution in which
    a+b=-2√(1+√2)

  • @ohiyo_o7637
    @ohiyo_o7637 2 місяці тому +2

    My approach is:
    (a+b)(a-b)=4
    (a^2+b^2+4)(a^2+b^2-4)=16
    (a^2+b^2)^2=32
    a^2+b^2=4root(2) (notice that a^2 and b^2 are both positive, so no plus or minus sign is needed for this square root)
    (a+b)^2=4root(2)+4
    a+b=plus or minus 2root((root(2)+1))

  • @ohiyo_o7637
    @ohiyo_o7637 2 місяці тому +1

    i got a+b = root( root(32)+4 ), is it correct or where did i do it wrong

    • @ohiyo_o7637
      @ohiyo_o7637 2 місяці тому

      oh it is the same thing, i just didnt simplify it, i am not very good at math haha

    • @damyankorena
      @damyankorena 2 місяці тому

      √32=4√2
      So
      √(4+√32)=√(4+4√2)
      = 2√(1+√2)
      Therefore they are equal

    • @ohiyo_o7637
      @ohiyo_o7637 2 місяці тому

      I see, thank you