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I am trying to plot a function over a tirangular region

   F[x_, y_] := -(0.1/x)*(Log[(x - y)/0.1])
   Plot3D[F[x, y] , {x, 0.1, 3}, {y, 0, 5}, 
   RegionFunction -> Function[{x, y}, x > y], 
   PlotRange -> {-2, 1}, AxesLabel -> Automatic, Mesh -> 60]

and I get some a jagged surface on one boundary.

I appreciate the surface is very steep on the $x=y$ line, and it could pose numerical difficulties.

Yet, is there a workaround to obtain a more aesthetically pleasing plot?

Thanks

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  • 1
    $\begingroup$ can't run your code. F100234 not defined. $\endgroup$
    – Nasser
    Commented Feb 11, 2020 at 8:37
  • $\begingroup$ My apologies, should be corrected now, thanks $\endgroup$
    – Smerdjakov
    Commented Feb 11, 2020 at 8:40
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    $\begingroup$ I get different plot. V 12. Screen shot !Mathematica graphics $\endgroup$
    – Nasser
    Commented Feb 11, 2020 at 8:44
  • $\begingroup$ Adding PlotPoints -> 100 might help. $\endgroup$
    – Henrik Schumacher
    Commented Feb 11, 2020 at 8:46
  • $\begingroup$ @Nasser, please consider my further edit, I have checked it now twice, sorry. $\endgroup$
    – Smerdjakov
    Commented Feb 11, 2020 at 8:49

1 Answer 1

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Add Boole to the plot argument:

Plot3D[F[x, y] Boole[x >= y], {x, 0.1, 3}, {y, 0, 5},RegionFunction -> Function[{x, y}, x > y], PlotRange -> {-2, 1},AxesLabel -> Automatic, Mesh -> 60]

enter image description here

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2
  • $\begingroup$ works well, thanks $\endgroup$
    – Smerdjakov
    Commented Feb 11, 2020 at 20:21
  • $\begingroup$ You're welcome. $\endgroup$
    – Ulrich Neumann
    Commented Feb 11, 2020 at 21:55

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