
Re: plotting integrals
Posted:
Sep 21, 2013 4:24 AM


Am Freitag, 20. September 2013 12:52:58 UTC+2 schrieb Herman: > 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}]
I don't understand why you still have the variable x which was integrated "away" in NIntegrate.
Ok, here is a piece of code very similar to yours which works. Maybe it is close to what you intended ...
\[Psi][x_, \[Omega]_] := (\[Omega]/Pi)^(1/4)* Exp[(2^(1))*\[Omega]*x^2] \[Psi]1[x_, a_, n_] := Sqrt[(2*n)!!/((2*n  1)!!*Pi)]*Cos[a*x]^n fTPT[a_, n_] := NIntegrate[\[Psi]1[x, a, n]*\[Psi][x, a*Sqrt[2*n*(n  1)]], {x, Pi/ 2, Pi/2}] etaB[a_, n_] := Sqrt[1  fTPT[a, n]] Plot[etaB[a, 3], {a, 0, 10}]
Best regards, Wolfgang

