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How do I could solve a equation

  1. #1
    Joe Satriani
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    How do I could solve a equation

    I have this equation :
    (1/Do^4)*(T4+T2/Do)=T1-T3
    T1, T2, T3 and T4 are known.
    I need to find Do.

    How may I solve this using EXEL ?
    Thanks,








  2. #2
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    It doesn't look like this equation has an analytic solution, so it will probably have to be solved numerically. Standard approach:

    1) Arrange equation so it is in the form f(x)=0. One way in this case (1/Do^4)*(T4+T2/Do)-T1+T3=0
    2) Choose a value for Do that appears to be near the solution.
    3) Numerically solve the equation. The Solver add-in is a utility in Excel that can do this. If you need help using Solver, let us know.
    4) Double check to make sure the solution found by Solver is reasonable.

    In some cases, there can be more than one solution. Choice of initial guess will determine which solution is found. In cases where multiple solutions are possible, it will be up to you to determine which is meaningful.

  3. #3
    Joe Satriani
    Guest

    Re: How do I could solve a equation

    Thank you MrShorty,

    Yesterday I tried to solved using Do = f(Do). I deactivated the automatic
    calculation and used F9 to do it manualy (~ Gauss Seidel approach).
    So, as you said, it could be solved numerically ....

    Thank you very much for spending you time and help me. I really appreciated
    it.

    Best Rgds,
    Satriani

    "MrShorty" wrote:

    >
    > It doesn't look like this equation has an analytic solution, so it will
    > probably have to be solved numerically. Standard approach:
    >
    > 1) Arrange equation so it is in the form f(x)=0. One way in this case
    > (1/Do^4)*(T4+T2/Do)-T1+T3=0
    > 2) Choose a value for Do that appears to be near the solution.
    > 3) Numerically solve the equation. The Solver add-in is a utility in
    > Excel that can do this. If you need help using Solver, let us know.
    > 4) Double check to make sure the solution found by Solver is
    > reasonable.
    >
    > In some cases, there can be more than one solution. Choice of initial
    > guess will determine which solution is found. In cases where multiple
    > solutions are possible, it will be up to you to determine which is
    > meaningful.
    >
    >
    > --
    > MrShorty
    > ------------------------------------------------------------------------
    > MrShorty's Profile: http://www.excelforum.com/member.php...o&userid=22181
    > View this thread: http://www.excelforum.com/showthread...hreadid=515373
    >
    >


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