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Math Help - Help with exponential equation calculation

  1. #1
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    Help with exponential equation calculation

    Hi i am trying to work out the following equation to get graph some theoretical results but think i am doing it incorrectly.

    The equation is A = 100 x e^-(100 * exp-((σ*ppm * Na *l * 100)/(w * d * 10^6))

    Now i am using excel so does the equation above equate to the expression below to work it out in excell?
    A= 100 x EXP((-σ*ppm * Na *l * 100)/(w * d * 10^6))

    My values are
    σ = 1.34E-20
    ppm = 100
    Na = 6.023 x 10^24
    l = 100cm
    w = 26.037354
    d = 911.8263883

    The value i am getting is 71.18439629
    which i think is wrong so either i am working out the equation incorrectly. I would just like to know if my calculations are being carried out correctly thanks
    K
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by k241 View Post
    Hi i am trying to work out the following equation to get graph some theoretical results but think i am doing it incorrectly.

    The equation is A = 100 x e^-(100 * exp-((σ*ppm * Na *l * 100)/(w * d * 10^6))

    Now i am using excel so does the equation above equate to the expression below to work it out in excell?
    A= 100 x EXP((-σ*ppm * Na *l * 100)/(w * d * 10^6))

    My values are
    σ = 1.34E-20
    ppm = 100
    Na = 6.023 x 10^24
    l = 100cm
    w = 26.037354
    d = 911.8263883

    The value i am getting is 71.18439629
    which i think is wrong so either i am working out the equation incorrectly. I would just like to know if my calculations are being carried out correctly thanks
    K
    since your original eqiation contains two nested exponential functions, and your excel expression just one the excel expression is wrong.

    RonL
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