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Re: Ambiguity of "Plot"

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  • Subject: [mg127808] Re: Ambiguity of "Plot"
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Thu, 23 Aug 2012 20:49:34 -0400 (EDT)
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You don't have correct Mathematica syntax to denote functions. Did you look at the many examples provided in the documentation? or make use of the Classroom Palette, say, to get a template for Plot?

First, you need:

  f[\[Alpha]_] := =85

where the argument is enclosed in square brackets rather than parentheses and where you need to indicate that \[Alpha] is a pattern variable by using the underscore character after it.

Second, in the Plot expression, you need again to use square brackets to surround the argument, that is, use f[\[Alpha]] instead of parentheses.

Third, to denote the plot domain, for the second argument to Plot you have to use the list

  { \[Alpha], 0, 1}

like that rather than including the inequality 0 < \[Alpha] < 1

After those ecorrections, of course you need to give a numerical values to the parameters \[Rho] and \[Delta] before having any hope of obtaining any plot whatsoever.


On Aug 23, 2012, at 2:54 AM, JikaiRF at aol.com wrote:

> I have been embarrassed about a function Plot.
> I would like to plot a curve defined as follows:
>
> f(\[Alpha]) = (\[Rho] + \[Delta] - \[Delta] \[Alpha] - Sqrt[\[Delta]\[Rho] \
> \[Alpha] (1 - \[Alpha]) + \[Rho]^2 \[Alpha]])/((\[Rho] + \[Delta]) (1 \
> - \[Alpha])).
> Here, 0 < \[Alpha] < 1.
>
> And I programmed in this way;
> Plot[f(\[Alpha]), { \[Alpha],  0 < \[Alpha] < 1}]
>
> The curve I obtained from Mathematica is monotonously decreasing. AS a result, f(1) =0.
> However, by using  l'H=F4pital7 theorem, f(1) = 1/2 is correct.
> In this situation, I would like to obtain an accurate curve.
---
Murray Eisenberg                                     
murray at math.umass.edu
Mathematics & Statistics Dept.      
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                  413 545-2859 (W)
710 North Pleasant Street                      fax   413 545-1801
Amherst, MA 01003-9305








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