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Efried1-Visitor
1-Visitor
October 24, 2011
Question

embarrasing "not defined" in solve blocks

  • October 24, 2011
  • 13 replies
  • 10098 views

I'm rather frequently get stuck with Mathcad 14 claiming that a variable is not defined- but its not a variable but a function at the left side of a find statement,

The solve block indeed works pretty well with a vector on the left side of the find statement.

I have the impression that copying into a new sheet sometimes helps. I think this is an error by design.

any help is highly apreciated

thanks

13 replies

F
Fred_Kohlhepp23-Emerald I
23-Emerald I
October 24, 2011

Tracing and troubleshooting errors in Mathcad has long been an art form; like Microsoft's, the error messages only rarely point to the actual problem. (Believe it or not, things have actually improved since early days!)

Soldier on!

M
MikeArmstrong1-Visitor
1-Visitor
October 24, 2011

(Believe it or not, things have actually improved since early days!)

Still not up to scratch though Fred!!!!!

Mike

M
MikeArmstrong1-Visitor
1-Visitor
October 24, 2011

The solve block indeed works pretty well with a vector on the left side of the find statement.

I have the impression that copying into a new sheet sometimes helps. I think this is an error by

I find copying the equation side of the solve block and checking the units helps. Also, by copy/pasting somewhere outside the solve block you should find the undefined variables.

Mike

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    Efried1-VisitorAuthor
    1-Visitor
    October 25, 2011

    once I thought Umlaute is the problem, then all Variables and Functions have to be included in the solvefunction, but neither helps- attached the proof that it works with the vector asignement...

    M
    MikeArmstrong1-Visitor
    1-Visitor
    October 25, 2011

    Unfortunately there is not much I can do with a *.pdf. Can you not post the worksheet?

    Mike

    V
    VladimirN24-Ruby IV
    24-Ruby IV
    October 25, 2011

    Gerfried Cebrat wrote:

    ...I have the impression that copying into a new sheet sometimes helps. I think this is an error by design...

    Could you give an example (Mathcad worksheet)?

    E
    Efried1-VisitorAuthor
    1-Visitor
    October 27, 2011

    I was now trying the same thing with ODE solve and think it works. The problem in my previous attempt was an integral which had been evaluated numerically for the standard solve block and failed when using a function to solve for different parameters, at least that is my impression. Mathcad evaluates the parameters diferently.

    M
    MikeArmstrong1-Visitor
    1-Visitor
    October 27, 2011

    I'm sorry Gerfried, the help your going to receive will be limited if you do not provide a Mathcad worksheet.

    Mike

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    Efried1-VisitorAuthor
    1-Visitor
    October 28, 2011

    The solution provided by Andy in another forum was to remove the units in the variables in the find expression of the solve block - for example t.l/K.

    thanks to all for your endeavour

    E
    Efried1-VisitorAuthor
    1-Visitor
    October 31, 2011

    I'm sorry, I have to say that the removal of the units in the find statemnet results in wrong solving!

    So back to the start! The behavior of Mathcad s so strange that I insist that it is buggy.

    K
    ksmith-21-Visitor
    1-Visitor
    September 22, 2015

    This is an old thread, but a common error I've seen is if you have open solve blocks it will confuse things.

    For example:

    Define your variables

    "Given"

    "Given"

    Equation

    Find(x) -> 'variable not define'

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