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Re: Ambiguity of "Plot"


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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