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gLanzer1-Visitor
1-Visitor
November 18, 2010
Solved

explicit evaluation

  • November 18, 2010
  • 5 replies
  • 11432 views

hello

i just introduced to the explicit evaluation (just 2 days ago) and having some problems..

see attached

1) can i set a limit to the number of decimal places in explicit evaluations?

i tried limiting it in the "format > result", "tools > worksheet options" ..

i want to limit the decimal places of x2 (in the explicit evaluation of h2), i don't need that many decimal places displayed.

2) can the explicit evaluation use the latest value?

something like this

h2=80.431Btu/lbm

in

wt:=h1-h2 explicit h1,h2 -> 91.278Btu/lbm - 80.431Btu/lbm

NOT

wt:=h1-h2 explicit h1,h2 -> 91.278Btu/lbm - [ 0.9314...(84.56 ... )+ 24.511 Btu/lbm]

Best answer by wayne

gLanzer,

Use the float keyword on the Symbolic toolbar.

re-define h2 and h2=h2 float,2 prior to using in the equation, OK, or where h2 is originally calculated.

5 replies

W
wayne12-AmethystAnswer
12-Amethyst
November 18, 2010

gLanzer,

Use the float keyword on the Symbolic toolbar.

re-define h2 and h2=h2 float,2 prior to using in the equation, OK, or where h2 is originally calculated.

M
MikeArmstrong1-Visitor
1-Visitor
November 18, 2010

There's no need to use 'explicit' in your third example. It's not doing anything.

Clipboard01.jpg

Mike

V
ValeryOchkov24-Ruby IV
24-Ruby IV
November 18, 2010

I do not use explicit. It is impossibly with units.

I do so:

NotExplicit.PNG

M
MikeArmstrong1-Visitor
1-Visitor
November 18, 2010

Like below?

Clipboard012.jpg

Mike

W
wayne12-Amethyst
12-Amethyst
November 18, 2010

Thanks Mike

Should review before I post, The real answer was to use float on the variables before using in the equations with explicite, or expand in your case.

(By extrapolation, I am not doing anything right now either, should I delete myself?)

M
MikeArmstrong1-Visitor
1-Visitor
November 18, 2010

(By extrapolation, I am not doing anything right now either, should I delete myself?)

You displayed the use of integrals right the other day.

Mike

V
ValeryOchkov24-Ruby IV
24-Ruby IV
November 19, 2010

The main and fatal problem of the Explicit operator is that this operatot is one SYMBOLIC tool.

But symbolic tool of Mathcad cannot work with units, number formating tools, DLL-functions etc.

PTC must honestly say it to Mathcad-users!

But each serios Mathcad-sheeet must have units, DLL-functions etc

Two Example.

A Little task - a little problem

simple-explicit.png

A big task (with DLL) - a big/fatal problem:

not-simple-explicit.png

M
MikeArmstrong1-Visitor
1-Visitor
November 19, 2010

Valery,

Is this a bug?

Clipboard01.gif

Mike

R
RichardJ19-Tanzanite
19-Tanzanite
November 21, 2010

No. The symbolic processor does not understand units. It just sees mm and in as undefined variables. It's no different to writing 1*sakjas+1*sakldjka. It drops the numerical value because it's 1 and displays sakjas+sakldjka.

G
gLanzer1-VisitorAuthor
1-Visitor
November 21, 2010

thank all.

very helpful indeed.

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