2

Wrap Table in the first argument with Evaluate: ContourPlot[Evaluate @ Table[ x^2 + y^2 == k, {k, {.04, .09}}], {x, -.5, .5}, {y, -.5, .5}]


2

You can use ContourPlot, specify the desired contours, and also use a non-default ColorFunction option. I also needed to use ColorFunctionScaling so that function values are left alone. f[a_,b_] := (1-a)/(b+2) ContourPlot[f[a, b], {a, 0, 1}, {b, 0, 2}, Contours->{0, 1/4, 1/2}, ColorFunction -> Function @ Piecewise[{{Red, 1/4<#<1/2}, {...


2

One idea is to inverse scale the interpolation of the scaled vector field ${\bf F}(x,y)$, in which the scaling factor $\alpha(x,y)$ is zero at the singularities; or might describe the process as conjugating the interpolation operator $I$ by the scaling $\alpha$: $$ \alpha^{-1} \circ I \circ \alpha $$ However, after computing $\alpha \,{\bf F}$, one needs to ...


1

f[a_, b_] := (1 - a)/(b + 2) You can use a single RegionPlot: RegionPlot[{0< f[a,b] <= 1/4, 1/4 < f[a,b] <= 1/2}, {a, 0, 1}, {b, 0, 2}, PlotStyle ->{Blue, Red}, BoundaryStyle -> None] Alternatively, RegionPlot with the options MeshFunctions+Mesh+ MeshShading: RegionPlot[True, {a, 0, 1}, {b, 0, 2}, MeshFunctions -> {f[#, #2] &...


1

Try RegionPlot(I changed your example a little bit because of 0<f<1/2) Show[{ RegionPlot[0 < (1 - a)/(2 + b) < 1/4, {a, 0, 1}, {b, 0, 2},PlotStyle -> Blue], RegionPlot[1/4 < (1 - a)/(2 + b) < 1/2, {a, 0, 1}, {b, 0, 2},PlotStyle -> Red] }]


1

I made a similar animation once with plusses: I changed the shape of the plus to a square. Here is the code: \[CurlyPhi] = Tan[1/3.]; Clear[DrawPlus, MakeScene] DrawPlus[p : {x_, y_}, \[Theta]_] := Module[{line}, (*line=Polygon[{{1,1},{3,1},{3,-1},{1,-1},{1,-3},{-1,-3},{-1,-1},{-3,-\ 1},{-3,1},{-1,1},{-1,3},{1,3},{1,1}}];*) line = Polygon[{{3, 1}, {1, -...


1

You can use CompleteKaryTree to construct the left tree and process it to remove unwanted nodes to get the right tree: leftg = CompleteKaryTree[4,2, ImageSize -> 300, VertexStyle -> {_ -> Blue, Alternatives[2,4,8,3,7,15]-> Green}]; rightg = VertexDelete[leftg, Range[10, 13]]; Row[{leftg, rightg}, Spacer[10]] Highlighting edges: In each ...


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