Date: Sep 20, 2013 6:52 AM
Author: Herman
Subject: plotting integrals

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}]