Ugly fraction in a label

Question

I'm having difficulties in displaying a proper fraction in a label. Here's the 2D graphics which shows the problem :

PolarPlot[{
    LegendreP[5, Cos[theta]], 
    11/2 If[theta <= Pi,  1, -1]LegendreP[5, Cos[theta]]^2 Sin[theta]
    },
    {theta, 0, 2Pi},
    PlotStyle -> {
        Directive[Thickness[0.0025], Blue],
        Directive[Thickness[0.0025], Red]
        },
    PlotLabel -> Row[{
        Style[HoldForm[LegendreP[5, " cos \[Theta] "]], Blue, 16],
        "\n",
        Style[11/2 HoldForm[LegendreP[5, " cos \[Theta] "]^2 "sin \[Theta]"], Red, 16]
        }]
]

The label contains the fraction 11/2 which is badly formatted. I would like to have the fraction displayed as a small fraction in front of P_5(cos(theta))^2 sin(theta), without the big parenthesis.

Is that possible?

I am looking for a solution that works in Mathematica 7.

Answer 1

Based on @Mike's answer here, add ScriptLevel -> 1 to Style.

Mathematica uses the ScriptLevel value to determine when it should decrease the font size in equations. The script level increases with each nested fraction/subscript/superscript. I think that Mathematica switches to smaller fonts at a ScriptLevel of 1. In inline formulas (the ones you type with Ctrl-9 in text cells) the starting ScriptLevel is 1, thus fractions become small immediately. Otherwise it is usually 0, so the outermost fractions are large (but things written within them become small).

---

However, the ScriptLevel is already 1 in Column by default, as opposed to Row. Don't use Row[{..., "\n", ...}] if you mean a Column. You may want to specify alignment using the second argument of Column.

PolarPlot[{LegendreP[5, Cos[theta]], 
  11/2 If[theta <= Pi, 1, -1] LegendreP[5, Cos[theta]]^2 Sin[
    theta]}, {theta, 0, 2 Pi}, 
 PlotStyle -> {Directive[Thickness[0.0025], Blue], 
   Directive[Thickness[0.0025], Red]}, 
 PlotLabel -> 
  Column[{Style[
     "\!\(\*FormBox[\(\*SubscriptBox[\(P\), \(5\)](cos\\\ \
\[Theta])\),
TraditionalForm]\)", Blue, 16], 
    Style["\!\(\*FormBox[\(\*FractionBox[\(11\), \(2\)] \
\*SuperscriptBox[\(\*SubscriptBox[\(P\), \(5\)](cos\\\ \[Theta])\), \
\(2\)] sin\\\ \[Theta]\),
TraditionalForm]\)", Red, 16]}]]

All this ugly SuperscriptBox stuff that you see above will format nicely in the front end if you paste it back:

I typed it like this:

• type "x"
• select the x and press Control-Shift-T to convert to TraditionalForm
• position the cursor next to the x, then type the formula as you normally would

Personally I prefer to type formulae directly into a single string rather than try to mix strings with HoldForm in a complicated way.

Answer 2

Update: According to the OP's comment, he is looking for a solution that works in Mathematica 7. MaTeX requires Mathematica 10. I am leaving this answer here in case others find it useful, but note that it does not solve the OP's problem.

---

If you're fussy about formula formatting, you'll be better off using MaTeX.

MaTeX["\\frac{11}{2} P_5(\\cos \\theta)^2 \\sin\\theta", 
 "DisplayStyle" -> False]

I made MaTeX precisely because people I worked with were fussy about formatting.

---

Load package:

<<MaTeX`

Add the color package to the preamble and change to CM Bright sans-serif fonts:

SetOptions[MaTeX, 
 "Preamble" -> {"\\usepackage{cmbright}", 
   "\\usepackage{amsmath,amssymb}", "\\usepackage{color}"}]

PolarPlot[{LegendreP[5, Cos[theta]], 
  11/2 If[theta <= Pi, 1, -1] LegendreP[5, Cos[theta]]^2 Sin[
    theta]}, {theta, 0, 2 Pi}, 
 PlotStyle -> {Directive[Thickness[0.0025], Blue], 
   Directive[Thickness[0.0025], Red]}, 
 PlotLabel -> 
  MaTeX["{\\color{blue}P_5(\\cos\\theta)},\;\; \
{\\color{red}\\frac{11}{2} P_5(\\cos \\theta)^2 \\sin\\theta}", 
   "DisplayStyle" -> False, FontSize -> 16]]

Answer 3

I wasn't totally happy with this. Even in the LaTeX code by Szabolcs, the fraction is larger than the P right next to it. But this gives close to the same thing as his, but without an external package

PolarPlot[{
      LegendreP[5, Cos[theta]], 
      11/2 If[theta <= Pi,  1, -1] LegendreP[5, Cos[theta]]^2 Sin[
    theta]
      },
     {theta, 0, 2 Pi},
     PlotStyle -> {
           Directive[Thickness[0.0025], Blue],
           Directive[Thickness[0.0025], Red]
           },
     PlotLabel -> Row[{

    Style[HoldForm[LegendreP[5, " cos \[Theta] "]], Blue, 16],
            "\n",

    Row[Style[#1, Red, #2] & @@@ {{11/2, 
        8} , {HoldForm[
         LegendreP[5, " cos \[Theta] "]^2 "sin \[Theta]"], 16}}]
            }]
 ]