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ELSID1-Visitor
1-Visitor
Oct 4, 2012 6:15 PM UTC
Solved

Symbolics Help

Working with symbolics is not my strong point. Need a little help with questions on the sheet. Based off of Dr. Alan Stevens critical thickness insulation work. Mostly symantics ... so driving me crazy.

AlanStevensAnswer
19-Tanzanite
Oct 5, 2012 7:44 AM UTC
ElSid wrote:
Did not understand the second part
AlanStevens wrote:
--> Replace T.sat with either T.s or just Tsat (i.e. no subscript) It will then result in T.s - T.air rather than -(T.air - T.sat ) .

See attached.

Alan

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11 replies

RichardJ19-Tanzanite
19-Tanzanite
Oct 4, 2012 8:39 PM UTC

One thing you should always remember when using the symbolic processor is that it does not make implicit assumptions like you do. If it doesn't do what you expect then a liberal dose of the "assume" keyword can work wonders

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ELSID1-VisitorAuthor
1-Visitor
Oct 4, 2012 9:12 PM UTC

Arrg! I had the R and t>0 on a previous section ... thanks for the catch. Is there a way of forcing the 2pi to the numerator? What about the negative sign?

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RichardJ19-Tanzanite
19-Tanzanite
Oct 4, 2012 9:22 PM UTC

Solve first, then simplify to get rid of the weird formatting, then force the ln formatting.

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ELSID1-VisitorAuthor
1-Visitor
Sep 18, 2014 7:35 PM UTC

Revisitng a post with a file that I had working in MathCAD 14 and for some reason will not work in MathCAD 15 M030. Hoping the Collab can help. Problem starts with equation 5 where it appears I can not longer define a variable based on a symbolic. See screenshot

Capture.JPG

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Werner_E
Werner_E25-Diamond I
25-Diamond I
Sep 18, 2014 8:23 PM UTC

Thats "normal" (nevertheless strange) behaviour that you dont see a symbolic result when you use a symbolic inline evaluation in an assignment.

Simply evaluate P.F later and you will see the correct result.

1.png

You used a font which seems not to be installed on my machine, so the nominator is shown as a small rectangle.

Depending on how wide you'd like your sheet to be spread you might consider changing that.

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ELSID1-VisitorAuthor
1-Visitor
Sep 18, 2014 8:30 PM UTC

Werner,

MathCAD just crashed. Why did it work in MathCAD 14? You are correct and I will revise the sheet. I shouldn't have to to do this much re-work btween 14 and 15!

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