1. Joined
    20 Jan '07
    Moves
    1005
    20 Feb '07 21:013 edits
    If xy*y + ty +z = 0,

    Find y.
  2. Joined
    19 Jan '07
    Moves
    1793
    20 Feb '07 22:431 edit
    Originally posted by GinoJ
    If xy*y + ty +z = 0,

    Find y.
    y= (-t +or- sqrt(t^2-4*x*z))/(2x) -the quadriatic formula



    correct?


    Edit: I forgot some brackets
  3. Joined
    15 Feb '07
    Moves
    667
    20 Feb '07 22:471 edit
    The quadratic formula suggests 2 solutions.

    (-t - sqrt( t*t - 4*x*z)) / (2* x)
    (-t + sqrt( t*t - 4*x*z)) / (2* x)

    Derived by making a perfect square in order to remove the square function

    x*y*y + t*y + z = 0
    y*y + t*y/x + z/x = 0
    y*y + t*y/x = -z/x
    y*y + t*y/x + t*t/(4*x*x) = t*t/(4*x*x) - z/x
    (y + t/(2*x))^2 = t*t/(4*x*x) - z/x
    y + t/(2*x) = +- sqrt(t*t/(4*x*x) - z/x)
    y + t/(2*x) = +- sqrt((t*t - 4*x*z)/(4*x*x))
    y + t/(2*x) = 1/(2*x)*+- sqrt(t*t - 4*x*z)
    y= -t/(2*x) +- sqrt(t*t - 4*x*z)/(2*x)
    y= (-t +- sqrt(t*t - 4*x*z))/(2*x)
  4. Joined
    06 Jul '06
    Moves
    1163
    21 Feb '07 01:09
    Originally posted by geepamoogle
    The quadratic formula suggests 2 solutions.

    (-t - sqrt( t*t - 4*x*z)) / (2* x)
    (-t + sqrt( t*t - 4*x*z)) / (2* x)

    Derived by making a perfect square in order to remove the square function

    x*y*y + t*y + z = 0
    y*y + t*y/x + z/x = 0
    y*y + t*y/x = -z/x
    y*y + t*y/x + t*t/(4*x*x) = t*t/(4*x*x) - z/x
    (y + t/(2*x))^2 = t*t/(4*x*x) - z/x
    y + t/(2*x ...[text shortened]... +- sqrt(t*t - 4*x*z)
    y= -t/(2*x) +- sqrt(t*t - 4*x*z)/(2*x)
    y= (-t +- sqrt(t*t - 4*x*z))/(2*x)
    i don't even know who you are or where your from but i cn tell from your above post that you really really need to get out more and that your single
  5. Earth Prime
    Joined
    16 Mar '05
    Moves
    21936
    21 Feb '07 03:17
    Originally posted by iraqi insurgent
    i don't even know who you are or where your from but i cn tell from your above post that you really really need to get out more and that your single
    Perhaps you should stay in a day and study grammar.
  6. Joined
    20 Jan '07
    Moves
    1005
    21 Feb '07 05:17
    Originally posted by GinoJ
    If xy*y + ty +z = 0,

    Find y.
    (x)y*y + (t)y + (z) = 0
    m*m = t*t - 4xz
    (-t +/- m)/2x=y
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