# All Questions

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### How can I fix a threshold for points that I want to select in an image?

I would like to ask you how I can fix a number of points to show in a picture. In the previous post (Is it possible to get the coordinates only for the highlighted points from an image?), JimB ...
28 views

### Is it possible to keep only coloured parts in an image, removing all the rest (in greyscale)?

I would like to know if it is possible to keep only coloured parts (for example red eyes) from a b/w image, removing all the other parts not coloured (i.e. in grayscale or black and white). I was ...
116 views

### Building a nine - region cluster chart with Tooltip to display labels associated with 2D points

I'm attempting to build a nine-region cluster chart using Tooltip to display labels associated with 2-D points also displayed on it. I do NOT want to use "FindClusters". I want to design my own ...
3 views

### How to show legends verticaly using ParametricPlot and Show

I am trying to plot 10 different plot using Show[$\cdot$]. My code has the following form ...
35 views

### Plotting a function in 3 dimensions within a domain

In this paper: https://www.staff.science.uu.nl/~beuke106/HypergeometricFunctions/COGP.pdf Any help how to reproduce the plot in Figure:7 It’s the leading order of the complex function, Equation (...
24 views

### How do I import only the number and separate between 'n' and 'p'?

I have a file like this: ...
32 views

### How to put the plot together?

I have a very long code which at the end, I get two plot (main energy plot and energy bar attached pictures). I need these two plots next to each other (for paper). Problem is I can not save the ...
15 views

### Unable to Execute wolfram script by calling a package from Windows command line

I work on script which loads a package called test. Notebook Execution:- Input:- Needs["test"]; test["foo"] Output:- <...
53 views

### Help with unsolved indefinite integral ! $\int \!r\ln \left( r \right) \sqrt {ar+{b}^{2}+{r}^{2}}\,{\rm d}r$ [migrated]

I really need to solve this indefinite integral: $\int \!r\ln \left( r \right) \sqrt {ar+{b}^{2}+{r}^{2}}\,{\rm d}r$ It seems much more complicated than it looks. I have found a integral table ...
175 views

### Manipulate Slope

this is my code: ...
41 views

### Why OpenerView reduces the size of my equation

In this code the equation comes out with the right size. ...
61 views

### Problem with Solve in harmonic oscillator

Why is the result not Indeterminate? Solve[x == a Cos[ω t + ϕ] /. {x -> 0, t -> 0, ϕ -> π/2}, a] when the result ...
21 views

### Trying to solve equation with changing variables. However only care for the real positive answer number

Warning: very new to Mathematica Currently I am trying to solve for x, but the variable K changes. So I'd like a value for <...
40 views

### Intersection of a plane with surface of ListSurfacePlot3D

If I have a list of points in 3D space that are only roughly located on a surface, this surface can be visualized with ListSurfacePlot3D. How can I find the ...
35 views

### Mathematica code for bifurcation diagram in 3D

Good day. I need help with the code in mathematica to plot the bifurcation diagram (e vs z*) or (e vs x*), for the system ...
172 views

### Meaning of InterpolationOrder -> All for multidimensional interpolation

What specific method does Interpolation use for unstructured multi-dimensional data when we set InterpolationOrder -> All? ...
157 views

### Last@Accumulate not giving same result as Total

If I run the code: arr = Table[0.979, 249]; Last@Accumulate[arr] - Total[arr] on Mathematica 11.0 (Windows), I get the result ...
29 views

### Block diagonalizing a complex anti-symmetric matrix

I am going to evaluate the block diagonal form of few skew-matrices. When matrix elements are real I can simply follow the approach suggested in this thread which I have implemented that as ...
19 views

### Putting package documentation on Wolfram Cloud

So, I've finally released v1.0 of my EcoEvo package. Yay. Maybe I'll give an overview here soon. I'd also like to advertise to my colleagues, perhaps non-Mathematica users, who might use it. The ...
47 views

### Replicating results from Pierre Welander's paper (1956) : differential equation, integration, complex numbers and hyperbolic functions

I am trying to replicate some equations on the paper Wind Action on a Shallow Sea: Some Generalizations of Ekman’s Theory by Pierre Welander using Mathematica. My main objective is obtaining the ...
56 views

### Can I trust NMinimize

I have a function $f(x,y)$ for which Minimum[{f[ x, y], x > 0, y > 0}, {x, y}] does not find a solution. However, ...
46 views

### Notebook with version-dependent cells

I want to make a notebook with the following special feature: some of its cells show up only when the notebook is opened in for instance versions 11 and 12, but are hidden if the notebook is opened in ...
21 views

### Nested Table With Iterable Bounds

I have a set of data that looks vaguely like this: ...
81 views

### How do you implement metric tensor in Mathematica?

I'm trying to follow several tutorials on metric tensors. One of the common exercises is a polar metric. I'm stuck trying to implement this in Mathematica. According to the derivation, the polar ...
23 views

### Place two-dimensional Graphics object into three-dimensional Graphics3D object

I have a labelled two-dimensional Polygon that I render with Graphics. ...
25 views

### Series expansion with small complex components

I am trying to expand a polynomial. As it is conventional in physics, I want to put a small imaginary part to my coordinates. I work in lightcone coordinates, where the separation between is given by ...
27 views

### getting rid of the planes in SliceDensityPlot3D

I have a problem I would like to make a plot of a 3D density that looks similar with SliceDensityPlot3D with "ZStackedPlanes" options but without the God awful planes that appear, keeping only the ...
121 views

### Include boundary conditions in wave equation solver

I'm solving a wave equation using mathematica. I already included the initial displacement and velocity. However, I don't seem to be able to include boundary conditions $u(-\pi,t)=u(\pi,t)=0$. ...
2k views

### Formatting results of a polynomial long division

I am teaching polynomial long division to my high school students. Not a pleasant topic to have to cover. I went to use Wolfram|Alpha and obviously, internally, they have a really elegant way to ...
62 views

Please correct my interpretation of formulas by Pietro Majer from post. For equation $a=x+x^p$ one root is $x=a\sum\limits_{k=0}^{\infty}\frac{(-a)^{(p-1)k}}{(p-1)k+1} {{pk}\choose{k}}$ Wolfram ...
33 views

### Using a neural net to make predictions

I want to use a neural net to give predictions, but I am not sure where to start. I do know that I don't want to use the high-level Predict function. So what I ...
43 views

### Mathematica crashes with non-integer exponents using NDSolve

I want to solve a system of coupled PDEs. It works fine if I set $i=0.$ ($i$ is in the exponent of the PDEs) or $i=1.$ in the code. However, if I set, e.g., $i=0.1$ NDSolve crashes after a few seconds....
64 views

### Making ^ work as MatrixPower for matrices

I'd like my expressions like A^d get interpreted as MatrixPower[A, d] for matrix arguments A, any suggestions how to do this?
74 views

### Is it possible to get the coordinates only for the highlighted points from an image?

I would like to ask you if it is possible to get the coordinates or a couple of numbers that can give me the positions of the highlights points (selected using HighlightImage function) in an image. I ...
78 views

### Methods for ListPlot3D

In the documentation for ListPlot3D we see that there is the option Method, but which methods are avalaible? I cannot find a documentation page for it. If that is ...
53 views

### recurrence equation

The output of Mathematica is only a copy of the input. What am I doing wrong? ...
41 views

### What is wrong with my function call?

I'm writing a function and when I execute it, I get a message saying: ... function has no opening ]. If I remove the right square bracket, I get a message saying: ... needs more input Here ...
192 views

### Number of list elements less than a given integer

I'm trying to make a function whose input is a list, and that outputs a list for which the nth element is the number of elements in the input less than n. So far, I have ...
33 views

### How to associate the elements of a list to numbers?

I am having problems to understand the association function. I have a list of lists containing numbers: ...
16 views

### Exporting data from Wolfram Cloud

I have this table: data = Table[{x, y, Sqrt[r^2-x^2-y^2]-r+RandomReal[{0,0.005}]}, {x, 0, 2.5,0.5}, {y, 0, 2.5,0.5}]; How can I export it to a .txt file using ...
67 views

### Implementing the Peano-Baker Series with Mathematica

I would like to calculate the Peano-Baker series with mathematica, namely an integral expansion to approximate the state transition matrix: Say I have a matrix $A(t)$ and I want to calculate: \$\Phi(...
370 views

### MaxDetect speed

What's the fastest way to find the local maxima of a 2D list? E.g. ...
75 views

### Is it possible to make Decompose work with coefficients containing radicals?

It appears that Decompose works reliably only on polynomials with integer coefficients, although it seems to be not mentioned in the docs. Can I make it work (or ...
49 views

### Duplicate Tuples in two different ways

Writing: n = 3; Tuples[{"min", "MAX"}, n] I get: {{"min", "min", "min"}, {"min", "min", "MAX"}, {"min", "MAX", "min"}, {"min", "MAX", "MAX"}, {"MAX", "min", "...
63 views

### How can I add units to variables inside Manipulate?

I've created a Manipulate expression with many variables. I would like each of these variables to have associated units as in the standard Quantity[Value,"Unit"] so that I can easily enter the values ...
41 views

### Why Mathematica 9 doesn’t work for wave equation solutions?

I try to reproduce by Mathematica 9 the code in answer 1 in the following question: Solve 1D Wave Equation But MA gives the following error: Also I tried the code in the answer 1 of the following ...
82 views

### Error Message when nothing should be evaluated

When I try to define this simple function getCoeff[SeriesData[_, _, coeff_, _, _, _]] := coeff[[2]] I get an error: ...
71 views

### Daylight hours vs calendar date

Is there a way in Mathematica or Wolfram Alpha to get a plot of daylight hours vs calendar date and rate of change of daylight hours vs calendar date. Lets say I want the plot for latitude 45 degrees ...