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K
ksk_1059423212-Amethyst
12-Amethyst
March 8, 2023
Solved

Error in root function

  • March 8, 2023
  • 2 replies
  • 2017 views

Hi

I get an error in the root function when a variable exceeds a specific number. See attached file.

 

Thanks in advance

 

 

 

 

 

 

Best answer by Werner_E

I could open the sheet you posted here and now I found the offending position.

Looking closer at the function you are looking for its zeros and plotting it sure helps!

Maybe this is of help to you:

Werner_E_0-1678357434329.png

 

2 replies

W
Werner_E25-Diamond I
25-Diamond I
March 8, 2023

Looks like you attached the wrong file 😉

I could not open the file you sent via PM - I still use P6 and use a trick to be able to open files created with newer versions, as long as they don't use features like drop downs, etc.

When you use root as root(f(x),x,x1,x2), then f(x1) and f(x2) must have different sign. This is obviously not the case in your file.

So either change x1 and/or x2 accordingly, or use the root function with a guess value.

First define a (more or less accurate) guess value like x:=2 and then try root(f(x),x) = ...

The calculation may be sensitive wrt the guess value.

K
ksk_1059423212-AmethystAuthor
12-Amethyst
March 9, 2023

Nope, it should be the right one 🙂 It's the same worksheet as for my previous query, but with a new problem 🙂

ksk_10594232_0-1678344638310.png

ksk_10594232_1-1678344668224.png

Ok, thanks. I have made a try but can unfortunately not get around the problem. Since you have opened my worksheets before, I can't see why this couldn't be opened. 

 

Thanks for taking time. 

 

 

W
Werner_E25-Diamond IAnswer
25-Diamond I
March 9, 2023

I could open the sheet you posted here and now I found the offending position.

Looking closer at the function you are looking for its zeros and plotting it sure helps!

Maybe this is of help to you:

Werner_E_0-1678357434329.png

 

    M
    MartinHanak24-Ruby III
    24-Ruby III
    March 9, 2023

    Hi,

    if I open Error - Function values.mcdx in Prime 9.0 and run Calculate from Calculation tab then your error appears immediately. From my layman's point of view, there are errors in the file that you have to fix.

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