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1-Visitor
Aug 21, 2014 1:27 PM UTC
Solved

invalid argument, expecting an arithmetical expression

Hi All,

This is what it looks like. I was trying to get the real and imaginary part of a big symbolic expression and got the error. I also attached my file Anyone can help on this? Many thanks in advance!

issue.PNG

Regards,

Mingyu

Werner_E
Werner_EAnswer
25-Diamond I
Aug 21, 2014 4:01 PM UTC

Mingyu Yang wrote:

Thanks a lot for the screenshot. Let me tell you more about my goal please. I want to get the symbolic result of the real and imaginary parts in this worksheet and then get another set of real and imaginary parts in another worksheet. These two set of symbolic expression would be equal to each other, therefore I got two equations with two unknowns(Rbot&Ctop). I hope I could solve Rbot & Ctop in this way.........But it seems that the expressions are kinda intimidating......Do you think this is feasible?

So at the end you are only interested in a numeric solution for Rbot and Ctop? Then I guess you should be able to succeed. You won't need any symbolic calculations at all to do so. Get rid of all symbolic evaluations and just leave the functions as you had them defined. I guess you will have similar functions from your second sheet. Merge both sheet into one and take care to avoid identical fuctcion or variable names if yoo don't mean the same.

Then provide guess values for Rbot and Ctop and setup a numeric solve block with your two equations (Re(Vfbl(Rbot,Ctop))=Re(Otherfunction(Rbot,Ctop)), etc.)

Edit: See attached sheet.

9 replies

Werner_E
25-Diamond I
Aug 21, 2014 1:32 PM UTC

Your attachment is not a valid Mathcad sheet but a (rather useless as of the missing pictures) html page.

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myang1-VisitorAuthor
1-Visitor
Aug 21, 2014 1:54 PM UTC

Sorry about that.....What about this one? It should be good.

Thank you.

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Werner_E
25-Diamond I
Aug 21, 2014 3:10 PM UTC

Mingyu Yang wrote:

Sorry about that.....What about this one? It should be good.

Thank you.

Yes, and apart from a rather long calculation time and a daunting result I experience no problem. I am using Mathcad 15 M030.

I attach a partial screenshot and a pdf printout. But due to the way you had setup your page (page size, margins, portrait mode, overlapping regions, placing regions way over to the right,...) I guess its sure hard to read.

Do you really need the symbolic result?

1.png

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