Why does the coordinate value containing fractions in this code show a formatting error when display

Questions
1

{pM = {3/2, Sqrt[3]/2}, pA = {0, Sqrt[3]}, pB = {3, 0}};
ContourPlot[Evaluate@{x^2/9 + y^2/3 == 1}, {x, -3.5, 4}, {y, -2, 3},
Epilog → {MapThread[
Text[#1 <> ToString@#2, #2, {-1, -1}] &, {{“M”, “A”,
“B”}, {pM, {0, 2}, {3, 0}}}]}, Frame → False, Axes → True,
AspectRatio → Automatic, AxesLabel → {“x”, “y”},
AxesStyle → Arrowheads@0.025, PlotLegends → “Expressions”]

2025-10-08_143038.png
2025-10-08_143038.png776×521 26.5 KB

The goal is to have the coordinate values of point M displayed as exact values {3/2, Sqrt[3]/2} in the image. How should the code be modified?

2

This is just a consequence of using ToString on an expression that isn’t simple “one dimensional” text. Just look at the output of

ToString[{3/2, Sqrt[3]/2}]

So, you either need to force your expressions to be “one dimensional” or you need to just not use ToString. For examples:

Epilog -> {MapThread[Text[#1 <> ToString[#2, InputForm], #2, {-1, -1}] &, {{"M", "A", "B"}, {pM, {0, 2}, {3, 0}}}]}

Epilog -> {MapThread[Text[Row[{#1, #2}, " : "], #2] &, {{"M", "A", "B"}, {pM, {0, 2}, {3, 0}}}]}
3

The problem has been solved in two ways. Thank you very much for your help.

4

Epilog → {MapThread[
Text[TraditionalForm@
Row[{#1,
“(” <> ToString[TraditionalForm@#2[[1]]] <> “,” <>
ToString[TraditionalForm@#2[[2]]] <>
“)”}], #2, {-1, -1}] &, {{“M”, “A”, “B”}, {pM, pA, pB}}]}

According to Eric Rimbey’s answer, the output format of handwritten coordinates can be slightly modified.

5

One more variation:

MapThread[Text[TraditionalForm[#1 @@ #2], #2, {-1, -1}] &,
 {{M, A, B}, {pM, {0, 2}, {3, 0}}}]
6

This method is great, and it’s more concise. Thank you for your help!