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rscott6-Contributor
6-Contributor
December 15, 2019
Question

Variable undefined, what am i doing wrong

  • December 15, 2019
  • 2 replies
  • 1592 views

I have no idea what im doing wrong as usual with Mathcad. I have been forced to go back to Mathcad 15 because i no longer have prime.

Why am I getting an error that says undefined variable.

 

I am defining a few variables above that are hard set

 

 

 

 

 

 

 

Defined above
Rin:= 100
DeltaV := .04

Intial Guess

out:=100

given
V = DeltaV * (out/Rin)
Av = out / Rin

find (V,Av) = 

And all i get is variable undefined

 

 

 

 

 

 

 

Im sorry, I don't know why it wont let me post the code. The sudo code is above I have double and tripled checked syntax. I am obviously not getting this. I absolutely hate 15 I can do this in prime with my eyes closed  

2 replies

L
LucMeekes23-Emerald IV
23-Emerald IV
December 15, 2019

If you want to solve V and Av, you HAVE to provide initial guesses for V and Av...

LucMeekes_0-1576446627353.png

 

 

Success!
Luc

    W
    Werner_E25-Diamond I
    25-Diamond I
    December 15, 2019

    Obviously you are missing the guess values for the variables you are looking for.

    I wonder why you are using a solve block for this, as you could calculate Av and V also directly using the values you defined earlier.

    Werner_E_0-1576446985573.png

    out is NOT a guess value, as you write, because out is not a searched for variable. So out will hold its initial value 100 throughout.

    Looks like you had something different in mind.

     

    You sure should be able to attach your Mathcad worksheet. What problem do you experience when you try to attach it here (you sure can't embed it, of course) ?

     

    BTW, switching from Prime to Mathcad 15 is not a step backward. Rather the opposite, given that MC15 is much more capable.

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