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Student Support Forum: 'RegionPlot3d - wrong output' topicStudent Support Forum > General > Archives > "RegionPlot3d - wrong output"

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Author Comment/Response
Alex
03/04/13 07:30am

Hello!

I am trying to illustrate the following area graphically in (K1,K2,K3) diagram:

K1 <= -1
K2 <= -1.5
K3 <= -2.5
-10 - K1 - K2 - K3 <= -4
K1 + K2 <= -3
K1 + K3 <= -4
K2 + K3 <= -4
K1 + K2 + K3 <= -5.5

I can see that the following two points do satisfy these inequalities (should be inside the area):
(-1, -2, -3) and (-1.5, -1.5, -2.5)

I use the following code:

Show [RegionPlot3D[
K1 <= -1 && K2 <= -1.5 && K3 <= -2.5 && -10 - K1 - K2 - K3 <= -4 &&
K1 + K2 <= -3 && K1 + K3 <= -4 && K2 + K3 <= -4 &&
K1 + K2 + K3 <= -5.5, {K1, -2.5, 0}, {K2, -2.5, -1}, {K3, -4, -2},
AxesLabel -> Automatic, PlotStyle -> Opacity[1]],
ListPointPlot3D[{{-1.5, -1.5, -2.5}},
PlotStyle -> Directive[Green, PointSize[0.01]]],
ListPointPlot3D[{{-1, -2, -3}},
PlotStyle -> Directive[Blue, PointSize[0.01]]]]


which gives me an area where the two points are OUTSIDE the area, which is wrong, as they do satisfy the inequalities.

Am I doing something wrong, or is it a Mathematica Error? I am using Mathematica 8. Will it help to upgrade to the new 9th version?

Thank you very much for your time and consideration!

Alex

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Subject (listing for 'RegionPlot3d - wrong output')
Author Date Posted
RegionPlot3d - wrong output Alex 03/04/13 07:30am
Re: RegionPlot3d - wrong output jf 03/04/13 11:48am
Re: RegionPlot3d - wrong output Alex 03/11/13 07:40am
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