In the attached figure, I am plotting the angle used in a book exactly with the same parameters with same units, but I am getting a totally different graph values. I am unable to solve it, kindly sort it out.
The codes I am using are stated as below
Double angle theta:
rm = 1/2 (3 M + Sqrt[9 M^2 - 8 Q^2]);
bc = rm^2/Sqrt[rm M - Q^2];
\!\(\*OverscriptBox[\(a\), \(_\)]\) = rm/Sqrt[-4 Q^2 + 3 M rm];
\!\(\*OverscriptBox[\(b\), \(_\)]\) =
rm/Sqrt[-4 Q^2 + 3 M rm] (
Log[(8 (-4 Q^2 + 3 M rm)^3)/(
M^2 rm ^2 (-Q^2 + M rm)^2) (2 Sqrt[-Q^2 + M rm] -
Sqrt[-4 Q^2 + 3 M rm])^2]) - \[Pi];
\[Beta] = 0; DOL = 0.01; M = 10; Theta = 2 bc/DOL (1 + E^((
\!\(\*OverscriptBox[\(b\), \(_\)]\) - \[Pi] + \[Beta])/
\!\(\*OverscriptBox[
StyleBox["a",
FontSize->12], \(_\)]\)));
\[Beta] = 0; DOL = 0.01; M = 30; Theta1 = 2 bc/DOL (1 + E^((
\!\(\*OverscriptBox[\(b\), \(_\)]\) - \[Pi] + \[Beta])/
\!\(\*OverscriptBox[
StyleBox["a",
FontSize->12], \(_\)]\)));
\[Beta] = 0; DOL = 0.01; M = 60; Theta2 = 2 bc/DOL (1 + E^((
\!\(\*OverscriptBox[\(b\), \(_\)]\) - \[Pi] + \[Beta])/
\!\(\*OverscriptBox[
StyleBox["a",
FontSize->12], \(_\)]\)));
Plot[{Theta, Theta1, Theta2}, {Q , 0, 1}, PlotRange -> All,
PlotStyle -> {{Black}, {Red, Dotted}, {Blue, Dashed}, {Green, DotDashed}},
FrameLabel -> {"\!\(\*
StyleBox[\"Q\",\nFontSize->16]\)", "\!\(\*
StyleBox[\" \!\(\*SubscriptBox[\(\[Theta]\), \
\(+\)]\)-\!\(\*SubscriptBox[\(\[Theta]\), \(-\)]\)[\[Mu] arcsecond]\",\n\
FontSize->16]\)"}, Frame -> True, Axes -> False]
Kindly help me.