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8
votes
1answer
121 views

ImageTransformation: polar to cartesian

I am working on something that requires the polar transformation of some images. I implemented this transformation with ImageTransformation: ...
0
votes
0answers
59 views

Why does Mathematica have trouble with this simple set of simultaneous equations? [on hold]

The code in question is: Solve[{x == r*Cos[\[Theta]], y == r*Sin[\[Theta]]}, {r, \[Theta]}]. I'm a newbie so this might be fairly basic, but shouldn't this work? ...
7
votes
2answers
335 views

Mapping data on Archimedes' spiral

I would like to map my data on Archimedes' spiral and preserve the distance between points on the curve. The test data consists of 20 evenly spaced {x,y} ...
1
vote
1answer
88 views

Using spherical derivatives with NDSolve

I am trying to plot the path of an object around a centre of mass. Obviously this needs spherical coordinates. The problem I encounter is with the derivatives. The Derivatives in spherical coordinates ...
2
votes
1answer
85 views

Plotting in projective space

I am having difficulty figuring out how to plot to projective space. Suppose I have a region which I have plotted such as: ...
0
votes
0answers
50 views

Geometric Transformation not working - degenerate points?

I've successfully used FindGeometricTransformation to project the simplex triangle onto the x-y plane: ...
1
vote
2answers
95 views

What is the 'Mathematica-way' to test a variable transform?

Hello Mathematica experts. I would like to play around with a simple variable transformation, to test some claims about it. I wonder if there is a Mathematica-like way to do this. The specific case ...
1
vote
0answers
79 views

How to construct a coordinate system that owns detailed calibration in the 3D enviroment?

Recently,I write a program to demonstrate the forward kinematics of the SCARA robot.The code showed as below: Using this function to construct the BigArm and ...
1
vote
2answers
222 views

How to make Mathematica use the chain rule?

Lets say I have the following PDE: $$x^2 u_{xx} - u_{yy} + u_y = 0$$ And I have the following change of variables: $$ s(x,y) = x e^y \, \, \, , \, \, t(x,y) = x e^{-y}$$ How can I use Mathematica ...
3
votes
1answer
199 views
0
votes
0answers
72 views

How to make MousePosition be referenced by a coordinate system established over an image?

In the question of How to make a curve selectable from a scaned image and convert it to a list of coordinates, thanks to the excellent answer of Alexei Boulbitch, I knew how to select a series of ...
2
votes
1answer
398 views

Time derivative of unit vector in spherical coordinates

Is it possible to take a time derivative of a vector given in some curvelinear coordinate system (i.e. spherical)? Mathematica would need to take into account the time dependence of the basis vectors. ...
1
vote
1answer
50 views

CoordinateTransformData that works for any dimension

The function CoordinateTransformData in Mathematica only works for three dimension. For example, ...
4
votes
1answer
188 views

Plot a cone in spherical co-ordinates

As we all know in spherical coordinates a function phi = π/3 gives us a cone. The cone makes an angle of π/3 with the imagined ...