# Regarding a contour plot [closed]

I have a function $$f(x, y) = \sin x\ \cos y\ \mathrm e^{x + y}$$ (just an example) such that $$x + y \le 1$$ (both $$x$$ and $$y$$ are positive and $$0 < x \le 1$$ and $$0 < y \le 1$$).

I want to make a contour plot such that the contraint $$x + y \le 1$$ is taken into consideration. By this I mean that for the value of $$x = x_0$$ the values of $$f$$ should be such that $$y = 1 - x_0$$.

## closed as unclear what you're asking by corey979, bobthechemist, bbgodfrey, Niki Estner, Αλέξανδρος ΖεγγDec 25 '18 at 5:51

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• Please phrase your question as a question and provide code showing where you are getting stuck. – bobthechemist Dec 20 '18 at 20:40

Plot3D[Sin[x] Cos[y] Exp[x + y], {x, 0, 1}, {y, 0, 1},
RegionFunction -> Function[{x, y}, x + y < 1],
MeshFunctions -> {#3 &}, Mesh -> 5,
MeshStyle ->Directive[Thickness[0.01],Red]] or

ContourPlot[Sin[x] Cos[y] Exp[x + y], {x, 0, 1}, {y, 0, 1},
RegionFunction -> Function[{x, y}, x + y < 1],
MeshFunctions -> {#3 &}, Mesh -> 5,
MeshStyle -> Directive[Thickness[0.01], Red]] • Thank you @David G. Stork. Could you suggest some nice PlotLegend? – Zilch Dec 20 '18 at 14:05
• Depends what you're trying to show: PlotLegend-> "my legend" or "Cost of soybeans in 1974" or whatever... – David G. Stork Dec 20 '18 at 14:07