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Numerically Solve

  1. Oct 12, 2009 #1
    I need to solve this implicit function of the catenary

    k=cosh(k/sqrt(k^2-1))

    how do i Do this in mathematica?
     
  2. jcsd
  3. Oct 12, 2009 #2

    lurflurf

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    Homework Helper

    FindRoot[k==Cosh[k/Sqrt[k^2-1]], {k,guess}]
    Where guess is a guess of the answer.
     
  4. Oct 13, 2009 #3

    Hepth

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    Gold Member

    If you do a :
    Plot[{k, Cosh[k/Sqrt[(k^2 - 1)]]}, {k, 0, 4}]

    You can get an approximate guess to use lurflurf's suggestion, for the two roots.
    FindRoot[Cosh[k/Sqrt[k^2 - 1]] - k, {k, 0.6}]
    FindRoot[Cosh[k/Sqrt[k^2 - 1]] - k, {k, 2}]
     
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