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Re: plotting integrals

  • To: mathgroup at smc.vnet.net
  • Subject: [mg131689] Re: plotting integrals
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Sat, 21 Sep 2013 04:36:30 -0400 (EDT)
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Perhaps trying to evaluate the integrand at one particular value will give a clue to what's wrong:

  Subscript[\[Eta], B][0, 1, 3]
NIntegrate::itraw : Raw object 0 cannot be used as an iterator
Sqrt[1 - NIntegrate[\[Psi]1[0, 1, 3]*\[Psi][0, 1*Sqrt[2*3*(3 - 1)]], {0, -Pi/2, Pi/2}]]

You're trying to integrate a function of "variable" that's actually the constant 0 !

On Sep 20, 2013, at 7:07 AM, Herman <btta2010 at gmail.com> wrote:

> Dear All,
>
> I would like to plot the function Subscript[\[Eta], B] but I got errors.
> Could someone please help me with these errors?
>
>
> \[Psi][x_, \[Omega]_] := (\[Omega]/\[Pi])^(1/4)
>  Exp[-1/2 \[Omega] x^2]
>
> \[Psi]1[x_, a_, n_] := Sqrt[(2 n)!!/((2 n - 1)!! \[Pi])] Cos [a*x]^n
>
> Subscript[F, TPT][x_, a_, n_] :=
> NIntegrate[\[Psi]1[x, a, n]*\[Psi][x,
>    a*Sqrt[2 n (n - 1)]], {x, -\[Pi]/2, \[Pi]/2}]
>
> Subscript[\[Eta], B][x_, a_,
>  n_] := Sqrt[(1 - Subscript[F, TPT][x, a, n])]
>
> Plot[Subscript[\[Eta], B][x, 1, 3], {x, -\[Pi]/2, \[Pi]/2}]

---
Murray Eisenberg                                    murray at math.umass.edu
Mathematics & Statistics Dept.      
Lederle Graduate Research Tower           
University of Massachusetts 
710 North Pleasant Street  
Amherst, MA 01003-9305








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