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Re: Help to a novice...

  • To: mathgroup at yoda.physics.unc.edu
  • Subject: Re: Help to a novice...
  • From: rubin at msu.edu (Paul A. Rubin)
  • Date: Mon, 20 Jun 94 12:40:30 EDT

>I received the following message from mathematica:
>
>s (0.5 + 0.5 Erf[5. (0.02 + Log[0.01 s])]) -
>
> 100. (0.5 - 0.5 Erf[0.2 - 5. (0.02 + Log[0.01 s])])
>Set::write:
>   Tag Times in (5. (0.02 + <<1>>))[s_] is Protected.
>
>The last two lines were in red , the ones before are o.k..
>What does it mean "Set ::write....."?
>
>Thanks a lot for your help in andvance.
>Yours Claus
>
>Swiss Institute of Banking and Finance
>
The "Set" in "Set::write" identifies the message as relating to the Set
command (the assignment operator); the "write" part designates the specific
error.  In this case, Mma apparently thought that you were trying to assign
a value to the expression 5. (0.02 + Log[0.01 s]), as if you had written

        5. (0.02 + Log[0.01 s]) = ...

The expression as you typed it in your message seems to be correct, but if
you copied the error message verbatim, the key clue might be the "[s_]" -
were you using that expression as if it were a function?  (To make it a
function, you can wrap it in the Function operator, as in "Function[ {s}, s
(0.5 + ... ) ]," or you can put an ampersand after it and replace the "s"
with "#", as in "# (0.5 + 0.5 Erf[5. (0.02 + Log[0.01 #])]) - ... )&".)

**************************************************************************
* Paul A. Rubin                                  Phone: (517) 336-3509   *
* Department of Management                       Fax:   (517) 336-1111   *
* Eli Broad Graduate School of Management        Net:   RUBIN at MSU.EDU    *
* Michigan State University                                              *
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Mathematicians are like Frenchmen:  whenever you say something to them,
they translate it into their own language, and at once it is something
entirely different.                                    J. W. v. GOETHE






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