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Re: beginner question regarding units in equations

  • To: mathgroup at smc.vnet.net
  • Subject: [mg123935] Re: beginner question regarding units in equations
  • From: Bill Rowe <readnews at sbcglobal.net>
  • Date: Sat, 31 Dec 2011 02:01:23 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com

On 12/30/11 at 7:09 AM, szhorvat at gmail.com (Szabolcs Horv=C3=A1t) wrote:

>On 2011.12.29. 8:53, RDog wrote:

>>Many civil engineering equations are empirically derived and
>>therefore the units dont work out exactly. How does Mathematica
>>handle units in equations and especially in empirical equations
>>where there may be parameters set to weird exponetial powers. Does
>>the program use units at all in equations or does the user need to
>>keep track?

>Mathematica does not know about units.  It does not keep track of
>units by default.  So you don't need to worry about units not
>matching.

>There is the Units` package which provides some limited support for
>units, but I have never used it seriously.  I think that not using
>units explicitly in your program will be the most productive way to
>work.

There is another package AutomaticUnits available at
<http://library.wolfram.com/infocenter/MathSource/7655/>

that significantly improves upon the Units package. Along with
other things you can do:

<< AutomaticUnits`

radius = r Centimeter;
area = Pi r^2;
Plot[area, {r, 0, 2}]

and get the desired plot without worrying about the units. A
much better solution than the Units package.




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