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0
votes
1answer
90 views

solve the iterative integral equatio

The following code is incorrect, please specify my mistakes ...
2
votes
2answers
16 views

How best to join tables, which have different lengths on the same column values which exist in both tables?

I think my problem is pretty simple, and in SQL this would be trivial. I have two tables ...
3
votes
2answers
72 views

To plot branch cut of logarithm

I like to see the branch cut of the function: $$1 - z \ln[(1+z)/z].$$ If I plot it in the complex plane: ...
0
votes
0answers
24 views

Why does Mathematica not evaluate this? Need help with symbolic integration

So I have f[x_] := g[x]/g'[x] FullSimplify[Integrate[f[x], x]] and I'm trying to get F(x) in terms of g(x) but it gives the random expression below as output ...
2
votes
2answers
76 views

Show two plots together: a two dimensional curve tangent to the maxima of a three dimensional plot

I have a list containing 3 columns and 6552 rows which can be found here. The plot of data is shown below: We have a cross cut ...
2
votes
1answer
53 views

Visualizing Riemann surface (two branches) of logarithm

I'm trying to plot two branches of the complex multi-valued function: (In a previous post - linked above-, Mathematica found the branch cut of the following function between -1 and 0) $1-z\ln[(1+z)/z]...
1
vote
1answer
11 views

Why won't this PrintTemporary[Dynamic[…]] expression work in a function?

I found myself reusing this code all the time to monitor variables during execution, so I'm trying to make it into a function: ...
1
vote
0answers
19 views

Solving infinite coupled equations

I need to solve symbolically an infinite system of coupled algebraic equations that I tried to do analytically but I could not. Solutions of these equations, $V_l^m$, define the coefficients of a some ...
0
votes
2answers
24 views

Edge list of a graph as a simple list of lists of pairs of integers?

Suppose I have a list of graph edges in the form: e={UndirectedEdge[1,2], UndirectedEdge[3,4]} How can I convert this to a simple list of lists: ...
8
votes
1answer
292 views

Is Mathematica's lexical scoping broken?

Why do these two lines output different things (b and 0, respectively)? Is it a bug? ...
4
votes
2answers
91 views

Problem combining ParametricNDSolve with NonlinearModelFit

Edited to add: The choices of Method given in the comments and in the answer provided by Tim work for the example I originally provided, and I thank all of you for those suggestions. Unfortunately, ...
1
vote
0answers
40 views

Expression manipulation

How can one write $\frac{ad+bc}{bd}$ in $\frac{a}{b}+\frac{c}{d}$ form? In other words, is there something opposite of Together[]? Edit My intend was to write <...
1
vote
0answers
40 views

Why do I always have a grey corner on my plot?

I have encountered a very wired plotting issue: I had a script to plot 6 triangles together in one graph as below (first figure). However, as you could see there are always two grey parts in the ...
0
votes
0answers
19 views

MaTeX in the labels

Writing Plot[Sin[2.5 x], {x, 0, 2}, PlotLabel -> Framed["a=1.5" // MaTeX]] I get the expected labeled plot: However, if I just change ...
0
votes
3answers
35 views

Optimizing with respect to the parameters of an optimization problem

I’ve got this simple loop that prints out the solutions to 2 simple equations for various values of parameters $a$ and $b$. I need to add a command that would display the parameter values that lead ...
3
votes
3answers
439 views

Plot a specific branch of a multi-valued complex function

Let's say I want to plot a branch of the following function $f(z) = \sqrt{z(z-1)}$. Let $z = r_1 e^{i\theta_1}$ and $z-1 = r_2 e^{i\theta_2}$. How can I tell Mathematica to plot the branch for which $...
1
vote
0answers
11 views

How can one remove the prefix /home/pi from Mathematica links to the web (e.g. documentation) on fresh raspberry pi 4 installation

With a fresh installation of Mathematica on a new raspberry pi 4, I find that the links to help and documentation and the Wolfram site are all erroneously prefaced by "/home/pi" which causes an error ...
1
vote
1answer
77 views

Greek letters don't depending of the font

For some reason mathematica (11.0.1 Windows 10 64-bit) does no use greek letter font from the selected font by FontFamily -> "AnyFont" When I check the ...
0
votes
1answer
91 views

Create a Miura origami pattern?

I want to solve the below code to create an origami pattern ...
0
votes
1answer
25 views

ListDensityPlot and interpolation order

I am working on a project that takes arrays of data and visualizes them using ListDensityPlot. I noticed, when I imported an array from a CSV file, the last column ...
0
votes
0answers
9 views

How to realise the backflow from one volume to the upper volume by modelica language?

It is a simple idea that I Want to solve the same equations in a finite volume when the variable x of next volume is computed smaller than 0. Because the characteristic of the modelica language, it is ...
7
votes
2answers
306 views

Animate flow lines of time-dependent 3D dynamical system

I've spent a bunch of time perusing Stack Exchange to try to find an answer and found nothing; hopefully this isn't a duplicate. I have a time-dependent vector field $\Phi_t(x,y,z)=(x\lambda^t,y\...
8
votes
4answers
644 views

Plotting in polar coordinates, simple implicit curves

How can I plot $\theta=\cos r$ in polar plane? Of course I know that it is different from $r=\cos \theta.$
0
votes
0answers
31 views
0
votes
0answers
34 views

“PermutationReplace[1,#1] cannot be used as a part specification” [on hold]

I am looking for all permutations of the standard coordinates on $\mathbb{R}^7$ that leave the 3-form $\varphi=dx_1 \wedge dx_2 \wedge dx_3 + \dots$ (this is a form with stabiliser $G_2$) unchanged. ...
1
vote
1answer
40 views

How to define NumberForm in LegendLabel?

To start: ...
5
votes
3answers
95 views

Including the actual length scale of the image in processing microscopic images

Following the wonderful methodologies provided in this post, I have learned how to process microscopic images of the types shown below in order to analyze them. When it comes to analysing the size ...
7
votes
4answers
210 views

Select elements of a list by comparing it to another list

Suppose I have the following lists: ...
3
votes
1answer
71 views

How to use indices during Map?

I want to map a function on each element at the "deepest" level of a list. The list can have an arbitrary number of dimensions. The function needs the indices of the element to which it is being ...
3
votes
1answer
53 views

Non-linear ODE from closed-loop system and Response

I started using Mathematica 12 and ran into difficulties. Namely, I want to compare the results of the calculation of a closed system from Simulink and in Mathematica. I rummaged around a bit on the ...
1
vote
1answer
34 views

Find the intervals where a piecewise is maximum

I have the following 3 piecewise functions and I would like to have the threshold of the upper envelope. ...
0
votes
0answers
22 views

Example with \$CharacterEncoding [on hold]

I'm looking for an example with $CharacterEncoding = None
0
votes
0answers
32 views

Analytic maximization that reduce fails to solve

I'm working on an interesting problem but stuck on a step that Mathematica fails on (no matter what angle I try to get at it from). I'm attempting to find the symbolic maximum of this convex function ...
2
votes
3answers
371 views

Symbolic Discrete Fourier Transform (DFT), using FFT?

Is there an implementation of a symbolic FFT in Mathematica? I've looked around, but I can't find any; Fourier seems to only give numerical results.
3
votes
4answers
156 views

Programming a recursive formula into Mathematica and find the nth position in the sequence

Well, I have the following recursive formula (where $\text{n}$ gives the position in the sequence): $$\text{P}_\text{n}=\alpha\cdot\text{P}_{\text{n}-1}+\text{P}_{\text{n}-2}\tag1$$ For arbitrary $\...
11
votes
3answers
559 views

Is it safe to Unprotect everything? What are the implications?

What is the reason for built-in symbols to be Protected? What happens if I Unprotect built-ins and add my own ...
1
vote
2answers
298 views

Solve an equation with specific domain?

How can I write a code in Mathematica to solve an equation with variable in specific domains? For instance, I want to write a code for ...
1
vote
2answers
35 views

Generating random variates inside summation

I'd like to generate a table of sums which each a non-correlated, normally distributed random variate inside. Here is the sample code: ...
3
votes
0answers
19 views

Canonical URL's for deployed notebooks changed?

I'm using the function below to update my notebooks in the cloud. Traditionally it deployed to the following location: https://www.wolframcloud.com/obj/yaroslavvb/whitening/curvature-unit-tests.nb I ...
10
votes
1answer
150 views

What is the best way to use errors in mathematica M12?

Since ErrorListPlot has been superseded by new functionality in ListPlot for Mathematica 12.0, what is the best way to handle ...
8
votes
5answers
362 views

Polar contour plot in Mathematica?

I am following a text on fluid mechanics with MAPLE examples. I want to do the following ContourPlot in Mathematica in Polar coordinates: $$ (r^2-\frac{a^3}{r}) \...
5
votes
1answer
73 views

Matching spectral data to known spectral lines

Preamble: I designed some code to help me take spectral images from a spectrometer and convert pixel number into wavelength. It does reasonably well at matching a calibration spectrum of a neon lamp ...
1
vote
1answer
46 views

Strange Startup Error Messages

Seemingly out of nowhere when I open Mathematica a messages window pops up with these two warnings. This issue starting occurring after no changes where made. ...
0
votes
1answer
30 views

remove one of the column in the output of Solve command

I would like to remove one variable in the output of the "Solve" command without changing the rest. For instance, in the following code ...
0
votes
1answer
102 views

Plotting rescaled time series and temporal data

I am trying to use ListLinePlot to plot three "Components" of my TemporalData in Mathematica. The three components differ widely in the range of the data. So, I want to Rescale each component and plot....
1
vote
0answers
27 views

Problems with the parametric Recurrence Table

I am trying to construct a minimization program where I have to minimize a function with respect to a matrix. This matrix enters into the optimization program in a convoluted manner together with data....
0
votes
0answers
31 views

NestList with LibraryFunction

For some reason using Nestlist with LibraryFunction can lead to kernel crash. It looks like something non-numerical is passed to LibraryFunction. There is no problem if the argument is checked, but my ...
0
votes
0answers
28 views

Using input in notebook TOC to Open at page 50 of a notebook

Already I have made a Table of Contents (TOC) notebook. In it are buttons which when pressed load very long notebooks, like say notebook ZZZ, which contains research notes. TOC works great. ...
0
votes
1answer
44 views

Solve integral equation by iteration

For[{n = 1, y[0][x_] = 1}, n < 4, n++, y[n][x_] = 1 + Integrate[y[n - 1][t]^2 + t^2, {t, 0, x}]; Print[{n, y[n][t]}]] here how can I get table of values ...
7
votes
4answers
387 views

How to obtain a subset (of a 2-d set of points with random coordinates) having monotonically increasing ordinates

If I start with a 2-d set of points: ...

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