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5
votes
1answer
83 views

Neumann boundary conditions in NDSolve over nontrivial region

The problem I would like to solve involves diffusion in the following region ...
7
votes
1answer
166 views

Plotting a region with polar axes

I want to plot the region of points who satisfy the following equation: 2 < r <= 5 && 3/4 π < θ <= 5/4 π I have been able to plot region in ...
3
votes
0answers
35 views

Bug when using Plot3D over an ImplicitRegion?

Evaluating this expression seems to cause Mathematica to beep and quit the kernel: ...
8
votes
5answers
315 views

How to generate random points in a region?

The Mathematica 10 documentation was updated for FindInstance adding support for regions. In my use case I'm trying to sample points in a set of disks: ...
7
votes
1answer
144 views

Strange behavior of `BoundaryMeshRegion`

BoundaryMeshRegion is new function of version 10. I am not familiar with the function. I want to decide whether a point is inside or outside in the Boundary using ...
4
votes
3answers
129 views

Regarding how to use Reduce

Say for example I am doing the following in Mathematica ...
0
votes
0answers
82 views

Parametric Plot not plotting all points

Basically I have a system of inequalities which I am solving and plotting using Mathematica. For example I have a system which has infinitely many solutions (it's unbounded). So I plot the system ...
3
votes
0answers
76 views

Precision problem while evaluating RegionMember or Element in V10

I'll try to give you a background on where the problem occured. The problem itself is defined near the end of the post. I'm running a sort of a simulation of a particle in a box. I finally got my ...
0
votes
1answer
63 views

3D Contour Plot parts of sphere with gradient less than 0, equal to 0 and more than 0

I want to plot only parts of the sphere of radius 1 where the gradient $\frac{\partial z}{\partial x}$ is < 0, = 0 and > 0. The full sphere is given by: ...
9
votes
2answers
204 views

Controlling quality of discretized region meshes

I want to discretize 3D constructive solids, supported by Mathematica 10 regions functionality. Quality of resulting meshes must be controllable, and meshes must be useful for further computation. ...
6
votes
1answer
107 views

Can't plot rotated region

I was experimenting with the code from this question when I ran into another problem with regions. ...
2
votes
0answers
74 views

Excluding region with `RegionDifference`

I can't make RegionDifference work for two Rectangle: ...
0
votes
1answer
65 views

Integral over geometric region [duplicate]

I'd like to calculate this integral $$ \int_E y\ dydz $$ where $E = \{ (x,y,z) \in R^3 : z^2+6 < y^2 < 5z \}$ By hand i've got $\frac{1}{12}$ but i'm not sure, and i'd like to verify this ...
-1
votes
3answers
132 views

Computing integral over explicit region [closed]

I need to integrate $f(x,y)=y^2-2x^2y+6x^3-3xy+2y-6x$ over $\{y\geq 2x^2-2, y\leq 3x\}$ Im using Boole in the following way; ...
4
votes
1answer
114 views

How can I prevent a Plot expression from evaluating points forbidden by its RegionFunction?

I just ran into this and it had me scratching my head for a good while. Say I have a function which may produce error messages for certain inputs, like e.g. ...
1
vote
2answers
73 views

Unknown limit of an array of area integrals

Could someone explain why Mathematica can't finish computing this limit (this is a limit of an array, when n -> Infinity (n ...
2
votes
1answer
132 views

How can I get dotted boundaries on a RegionPlot?

How do I plot something like $$\{(x,y): 1 \leq x^2 + y^2 < 9\}?$$ I want to be able to make the boundary $x^2 + y^2 = 9$ dotted line and the unit circle filled and coloured region in between? I ...
1
vote
0answers
106 views

ListDensityPlot: How to only retain regions with data without using interpolation?

I'm working with ListDensityPlot on a set of triples, $\{\{x_1, y_1, z_1\}, \dots\}$. The data is on a semi-regular grid and looks just as it should through most of ...
7
votes
2answers
209 views

Union of plotted regions as sum of colors

I wish to plot 2 functions $f$ and $g$ so that the region bounded by $f$ has color $c_f$, the region bounded by $g$ has color $c_g$, and the region bounded by both has color $c_f+c_g$. E.g. $c_f$ is ...
8
votes
4answers
643 views

Showing a rectangular plot on an almost-closed sphere

I am currently teaching some students about the "point at infinity", and how it allows us to treat circles and lines as "the same", etc. I would like to kind of show this happening with a series of ...
1
vote
1answer
126 views

Manipulate doesn't work for plotting a region where a matrix is positive semi-definite

I'm facing the following problem and would very much like you help. Thanks is advance! I have defined the following 4x4 matrix: \begin{equation} S=\left( \begin{array}{cccc} ...
3
votes
0answers
226 views

Use of RegionFunction with Graphics3D?

I'd like to plot in 3D a long list of polygons created with TetGenConvexHull, but only in regions specified by a function. Is that possible? As I have it my ...
0
votes
0answers
49 views

How to judge if a point is in the interior of a closed curve or not? [duplicate]

For example: pts = {{0, 1}, {-(Sqrt[3]/2), -(1/2)}, {Sqrt[3]/2, -(1/2)}}; trig=JoinedCurve[Line[pts], CurveClosed -> True]; Then ...
10
votes
3answers
500 views

How to remove unwanted regions in a three-dimensional surface

As the title indicates, I want to delete some unwanted regions in a three-dimensional surface created using ContourPlot3D. Here is the corresponding code ...
21
votes
3answers
896 views

RegionPlot3D in cylindrical or spherical coordinates?

RegionPlot3D is awesome. Unfortunately, it appears to work only for Cartesian coordinates. While there are ways to draw surfaces in spherical or cylindrical coordinates, I can't find a way to draw ...
2
votes
4answers
413 views

Highlight integer points in RegionPlot

Is there any way to mark integer points after plotting region in Mathematica? For example, if I: ...
9
votes
1answer
1k views

Using RegionFunction on multiple plots

I realize that the Plot function can plot multiple functions of x at the same time, using { }. I also know that the ...
3
votes
2answers
571 views

RegionPlot3D contour problem

I have a little problem and didn't succeed trying to solve it on my own. Situation is, I need a visualization of the function $s - 3\cdot s\cdot q + q$ as a region on p == 0 if function's value is ...
7
votes
2answers
367 views

Ideas on how to improve the rendering of the letter B in this 3D region plot?

I have been playing with the RegionPlot3D idea from this question and have been trying to approximate the Gödel, Escher, Bach logo, but I am a little bit stuck on how to improve the rendering of the ...