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Atomique131-Visitor
1-Visitor
March 1, 2019
Solved

problem with unit=0.0 when solve quadratic equation

  • March 1, 2019
  • 2 replies
  • 2300 views

Hello,

I am new to Mathcad,I have been using PTC Mathcad Prime 5 since yesterday.

I have a problem when I use solve and assume for this quadratic equation. All the variables have mm as unit. If I assume mm <> 0 then it works. The answer I am looking for is 233.41847464108950079 mm.

image.png

Ps. If I put = it shows the good answer (my bad, I was too frustrated about the if and else thing to try), but why does it show if and else? 

Thank you

Best answer by Werner_E

For numerical result (especially with units) you may consider using a numeric solve block instead of the symbolic solver:

B.PNG

2 replies

L
LucMeekes23-Emerald IV
23-Emerald IV
March 1, 2019

The symbolic processor in Mathcad (and Prime) does not know about units, it treats them as unknown variables.

You can write sol to be a function of Lp, Dp1 and Dp2, so instead of sol:=... you write sol(Lp,Dp1,Dp2):=...

Then you can evaluate sol(Lp,Dp1,Dp2)=

to get the answer.

 

Success!
Luc

    W
    Werner_E25-Diamond IAnswer
    25-Diamond I
    March 1, 2019

    For numerical result (especially with units) you may consider using a numeric solve block instead of the symbolic solver:

    B.PNG

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