(************** Content-type: application/mathematica ************** CreatedBy='Mathematica 5.2' Mathematica-Compatible Notebook This notebook can be used with any Mathematica-compatible application, such as Mathematica, MathReader or Publicon. The data for the notebook starts with the line containing stars above. To get the notebook into a Mathematica-compatible application, do one of the following: * Save the data starting with the line of stars above into a file with a name ending in .nb, then open the file inside the application; * Copy the data starting with the line of stars above to the clipboard, then use the Paste menu command inside the application. Data for notebooks contains only printable 7-bit ASCII and can be sent directly in email or through ftp in text mode. Newlines can be CR, LF or CRLF (Unix, Macintosh or MS-DOS style). NOTE: If you modify the data for this notebook not in a Mathematica- compatible application, you must delete the line below containing the word CacheID, otherwise Mathematica-compatible applications may try to use invalid cache data. For more information on notebooks and Mathematica-compatible applications, contact Wolfram Research: web: http://www.wolfram.com email: info@wolfram.com phone: +1-217-398-0700 (U.S.) Notebook reader applications are available free of charge from Wolfram Research. *******************************************************************) (*CacheID: 232*) (*NotebookFileLineBreakTest NotebookFileLineBreakTest*) (*NotebookOptionsPosition[ 7525, 221]*) (*NotebookOutlinePosition[ 8190, 244]*) (* CellTagsIndexPosition[ 8146, 240]*) (*WindowFrame->Normal*) Notebook[{ Cell[CellGroupData[{ Cell["Physics 70006 E&M I", "Subtitle"], Cell["Generalized Legendre Functions", "Subsubtitle"], Cell[CellGroupData[{ Cell["Conical Harmonics", "Subsection"], Cell[BoxData[ \(Clear["\<`*\>"]\)], "Input"], Cell["\<\ P[\[Nu], \[Theta]] is a generalized Legendre function. We want to force it to \ be a conical harmonic associated with opening half-angle \[Beta]. \ \>", "Text", FontColor->RGBColor[1, 0, 0]], Cell[BoxData[ \(P[\[Nu]_, \[Theta]_]\ = \ Hypergeometric2F1[\(-\[Nu]\), \[Nu] + 1, 1, \((Sin[\[Theta]/2])\)^2]\)], "Input"], Cell[TextData[{ "Let's consider a cone of opening half-angle \[Beta] = \[Pi]/6 \ (30\[Degree]). Our first goal is to estimate values ", Cell[BoxData[ \(TraditionalForm\`\[Nu]\_k\)]], " that put the 1st, 2nd, 3rd, ... zero of P at \[Beta] = \[Pi]/4." }], "Text", FontColor->RGBColor[1, 0, 0]], Cell[BoxData[ \(\[Beta] = \ \[Pi]/4\)], "Input"], Cell[BoxData[ \(Plot[P[\[Nu], \[Beta]], {\[Nu], 0, 20}, PlotStyle \[Rule] \ {Thickness[0.01], Hue[ .99]}, AxesLabel \[Rule] \ {\[Nu], "\<\>"}, TextStyle \[Rule] {FontSize \[Rule] 12}, PlotLabel\ \[Rule] \ "\
"]\)], "Input"],
Cell["\<\
From the graph, one sees that the approximate roots for this value of \[Beta] \
are at \[Nu]app = 2.5, 6.5, 10.5, 14.5, ..v (spacing is 4) . Now, let's \
obtain more precise values starting from \[Vee]app.\
\>", "Text",
FontColor->RGBColor[1, 0, 0]],
Cell[BoxData[
\(\[Nu]app\ = \ Table[\(-1.5\) + 4\ k, {k, 1, 7}]\)], "Input"],
Cell[BoxData[
\(FindRoot[P[\[Nu], \[Beta]] \[Equal] 0, {\[Nu], \[Nu]app}]\)], "Input"],
Cell[TextData[StyleBox["Assign these exact roots to rge array \[Nu]1 and \
check that P[\[Nu]1, \[Beta]] = 0",
FontColor->RGBColor[1, 0, 0]]], "Text"],
Cell[BoxData[
\(\[Nu]1\ \ = \ \[Nu] /. \ %\)], "Input"],
Cell[BoxData[
\(P[\[Nu]1, \[Beta]]\)], "Input"],
Cell[TextData[StyleBox["Plot the functions P[\[Nu]1[i], \[Theta]] from 0 to \
\[Beta]. The respective functions have a zero at \[Beta] and 0, 1, 2, 3, ... \
for \[Theta]<\[Beta].",
FontColor->RGBColor[1, 0, 0]]], "Text"],
Cell[BoxData[
\(\(\(\ \)\(Plot[{P[\[Nu]1[\([1]\)], \[Theta]],
P[\[Nu]1[\([2]\)], \[Theta]], P[\[Nu]1[\([3]\)], \[Theta]],
P[\[Nu]1[\([4]\)], \[Theta]], P[\[Nu]1[\([5]\)], \[Theta]],
P[\[Nu]1[\([6]\)], \[Theta]],
P[\[Nu]1[\([7]\)], \[Theta]]}, {\[Theta], 0, \[Beta]},
PlotStyle \[Rule] {{Hue[0], Thickness[0.008]}, {Hue[0.15],
Thickness[0.008]}, {Hue[0.30], Thickness[0.008]}, {Hue[0.45],
Thickness[0.008]}, {Hue[0.60], Thickness[0.008]}, {Hue[0.75],
Thickness[0.008]}, {Hue[0.90], Thickness[0.008]}},
AxesLabel \[Rule] \ {\[Theta], "\<\>"},
TextStyle \[Rule] {FontSize \[Rule] 12},
PlotLabel\ \[Rule] \ "\