problem with unit=0.0 when solve quadratic equation

[Atomique13]

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.

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

[LucMeekes]

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

[Werner_E · Accepted solution]

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