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use of ? when not meaning help

Trying desperately to understand Michael Trott's Happy Harmonic 2017! post: https://community.wolfram.com/groups/-/m/t/2858495 What does the use of ? in ?t1, ?t2 and ? = (t21 - t12)...mean? The ...
  • 1
0 votes
0 answers
8 views

0-1 test or Lyapunov exponent, to prove my below system is chaotic?

The following question is a part of my research here,I want to calulate the Lyaponov exponents of the following dynamics to show whether i have a chaotic dynamics or not. $$ \ddot{x}-ax+bx^{3}+cx^{5}...
0 votes
0 answers
9 views

Using NDSolve on piecewise-defined system of ODEs

I'd like to use NDSolve to solve a system of n coupled 1st-order linear ODEs expressed in matrix-vector form, but which are definied piecewise in n-space (in particular, to represent different linear ...
0 votes
1 answer
22 views

Determining size of the list top level

I would like to determine how many top level list elements I have. However, I need it to work like this: ...
  • 3,436
0 votes
0 answers
13 views

Singular Value Decomposition of a matrix over the complex plane using parallel table

I have a big matrix $M(z)$ where $z$ is a complex number. The matrix is also dense. I am trying to compute the smallest singular value of the matrix over the complex plane. Since the computation at ...
  • 301
3 votes
1 answer
17 views

Convert list of conditional expressions to list

I have a long list of items of the form ...
  • 4,045
0 votes
1 answer
25 views

Solving equations involving elliptic functions

I have this: sol = a^2 + b^2 - c^2 + 2 (c^2 - a^2)*JacobiDN[Sqrt[c^2 - a^2]*x, m] == u /. {m -> 1} And I want to find its inverse, i.e. express x in terms of u. ...
0 votes
0 answers
43 views

Pdf export is heavily flawed for simplest possible notebook such as a=b+c

File > save As ... > pdf (or print as pdf) gives me extremely bad results even for the most basic simplest possible Mathematica notebooks. Here a simple example where I can reproduce the problem....
  • 111
0 votes
0 answers
12 views

Why is Mathematica not solving a differential eigenvalue problem with Robin boundary condition correctly?

I am trying to solve for the natural frequencies of a rod vibration problem. The BVP to be solved is u''[x]+\[Omega]^2 u[x] == 0 subject to the boundary conditions ...
1 vote
0 answers
13 views

How to use RowReduce with AugmentedMatrix [duplicate]

I have used code in this post to reach the following for a classroom example that involves a 2d abstraction framed in a 3d illustration ...
  • 682
0 votes
0 answers
22 views

(Desmos) I'm getting the error "Too many variables", but I used only Latin letters [closed]

I don't know if I'm on the right place to ask desmos related stuff, but I'm not sure where else to ask, so here I go: I get the error "too many variables". I am using multiple variables as ...
0 votes
0 answers
10 views

Global fitting of multiple experimental datasets by solving ODEs under different conditions

I'm trying to perform global fitting analysis by solving ODEs for six different experimental datasets under different conditions. I tried to do it using MultiNonlinearModelFit and ParametricNDSolve, ...
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0 votes
0 answers
16 views

Finding the inverse function when we have Jacobi functions?

I have this function u = JacobiDN[Sqrt[b^2 - q^2]/k*k*x, m] /. {m -> 1} And I want to find the inverse, i.e., give it in terms of x instead of u I'm finding the ...
1 vote
3 answers
52 views

Evaluate using Mathematica or otherwise $\int_{0}^{\pi/2}\sin^n x \ T_n(\sin x)\ dx$

Denote $T_n(x)$ as Chebyshev polynomial of the first kind (see here). Then I need to evaluate for $n$ a odd natural number $$\int_{0}^{\pi/2}\sin^n x \ T_n(\sin x)\ dx $$ I am requesting a code with ...
  • 97
0 votes
0 answers
16 views

Cut a piece of an image and obtain FFT

I have an image that is all zero except for a square in the middle of it. Can I compute the fast Fourier transform (FFT) of that square which is smaller and less time-consuming and obtain the FFT of ...
  • 1
0 votes
0 answers
59 views

How to publish a Mathematica notebook to a journal as supplementary material?

I've done part of a proof via Mathematica. In the appendix of the paper I've linked to this published notebook, since I misunderstood "With any paid subscription plan, all files stored in the ...
  • 111
1 vote
1 answer
27 views

Plotting Polar Solution of NDSolve

I want to plot a solution to the Geodesic equations for the Poincare disk in polar coordinates (though these may be wrong. I want to plot these as a way to check my answer): $$\ddot{r}+\frac{2r}{1-r^2}...
  • 113
0 votes
0 answers
32 views

How to render text at a specific height in pixels?

I would like a way to create an image of text that is a specific height in pixels. In the following code, the text is sized to fit in the specified raster. Since there are five letters, we expect each ...
  • 1,907
1 vote
1 answer
71 views

Confusion about the code

1.First, I defined the spherical harmonic function and converted it to Cartesian coordinates. ...
  • 1,130
4 votes
0 answers
40 views

Difference between direct plotting and using function to plot

Edit: Syed's and Lukas's suggestions both solve this problem, thank you very much. I'm having some issues with a set of plots I'm making (it's to do with Penrose diagrams, but that's probably not of ...
  • 41
4 votes
1 answer
72 views

Finding positions of sublists matching a criterion

I want to find in a list of couples the positions of the ones with consecutive items: ...
0 votes
1 answer
69 views

I am trying to solve ODE using NDSolve mathematica [closed]

I will upload my code again after correcting Mista
4 votes
2 answers
80 views

How do I launch a kernel under Rosetta when I'm running the FrontEnd natively on Apple Silicon?

It's easy to launch a frontend under Rosetta, which will naturally start its kernels under Rosetta as well. For example, you can check a box in the Get Info window of Mathematica in the Finder, among ...
  • 13.9k
3 votes
0 answers
72 views

What's up with BarChart?

Mathematica version 13.2.1.0 macOS version Ventura 13.2.1 I began having odd behavior with BarChart. I restarted Mathematica. The attached image demonstrates the ...
  • 14.2k
0 votes
0 answers
19 views

FinancialIndicator does not work in InteractiveTradingChart with list form of stock data

I want to add some FinancialIndicator on InteractiveTradingChart when stock data is written in the form of list, ...
0 votes
0 answers
62 views

Evaluating Fourier transform in mathematica

I am trying to evaluate the expression FourierTransform[[m (a^2 - t^2 - I g t)]^-1, t, ω] in Mathematica. It gives me the error message that "Syntax: "[m(...
0 votes
0 answers
20 views

manipulating animation

The following code defines a function P[...,X,Y,...] and plots its (random) points with coordinates (X,Y) on a plane as an animation. The number of points is determined by the variable "particles&...
0 votes
1 answer
61 views

How to reproduce such Graphics3D? [duplicate]

The questioner asked how to reproduce a graphic that very closely resembled this graphic: Shortly afterwards, my browser crashed. meta.stackexchange.com states that they do not plan on supplying a &...
  • 497
0 votes
1 answer
46 views

Handling singularities like (x-y) in the denominator while evaluating double integrals

I have to solve an Integral of the following type ...
0 votes
0 answers
64 views

Approximating Exp[-x] in partial fraction form [duplicate]

I'm looking to obtain order-$k$ approximation of $\exp(-z)$ for real-valued $z$. $$R_k(z)\approx \exp(-z)$$ The constraint is that I need the result in partial fraction form, ie: $$ \begin{equation} ...
0 votes
0 answers
50 views

How to solve the problem with the error in FindRoot for non-linear equation?

Whoever is reading this have to be patient as the code is slightly long and I have explain each section in order to explain the problem. So I want to solve the set of non-linear algebraic equation ...
  • 559
0 votes
0 answers
22 views

How to increase precision close to a irregular singular point of a numerical solution?

Using for example an ODE like ode = t^3 y''[t] + t y'[t] + y[t] with the following boundary conditions ...
1 vote
1 answer
31 views

Why does the image of this parameterization appear disconnected?

Why the image of this parameterization appears disconnected. Thanks. ...
-2 votes
0 answers
80 views

How can I solve symbolically this coupled first order ODE? [closed]

S ⁢ a [ T ] ^ 3 + ( 1 / 2 ) * f ⁢ Cos [ γ [ T ] ] + a [ T ] ⁢ ( σ ⁢ ω - ω ⁢ γ ′ [ T ] ) ⩵ 0 and ...
0 votes
1 answer
45 views

Adding unit square axes to an array plot

I want to take the image created by ArrayPlot of a matrix A and add axes with the origin at the top left so that the image looks like the density plot of a function on [0,1]^2. ...
5 votes
0 answers
70 views

Using `Real32` numbers in Mathematica?

Is it possible to use Real32 format in Mathematica for matrix operations and does it make sense for performance? For high-dimensional vectors, high precision is an ...
4 votes
3 answers
139 views

HoldForm not working with Map

I am debugging a ListPlot implementation and I need to see the command. To avoid huge list of numbers, i just need the ListPlot ...
  • 3,436
1 vote
1 answer
51 views

Format[] and Power[]

Suppose I have a simple dot product function DP that I want to display nicely, I might use e.g. Format[DP[x,y],StandardForm]:= (x\[CenterDot]y) If x == y, then I'll ...
  • 695
0 votes
2 answers
75 views

Setting up a PDE for a time-independent Schrödinger equation

I am trying to solve a 2d Schrödinger equation with a non-separable potential because I want to calculate the probability of reflection for different angles of incidence of a plane wave. Here I ...
0 votes
1 answer
52 views

The code text3D facing the screen instead of rotating

As a known issue, Mathematica always keeps Text on top of everything in Graphics3D. There are some ways to avoid this, and one of them is wonderful function text3D: Placing text in 3D (not facing ...
  • 225
2 votes
0 answers
29 views

How to remove the background color for the regionfunction option in contourplot3D? [closed]

Suppose that I want to plot only a part of a given surface using ContourPlot3D, such as the upper hemisphere of a sphere. I could do this using the RegionFunction option as follows: ...
  • 193
0 votes
1 answer
84 views

Do Loop Complication [closed]

...
0 votes
1 answer
65 views

Finding inverse functions

Perhaps I'm not using the built in functions correctly, but I have a function f[x]. I want to find a function g[x] (its inverse) such that f[x]*g[x] = 1. This seems like something mathematica would ...
0 votes
0 answers
47 views

Redefining properties of objects already defined [closed]

...
2 votes
1 answer
79 views

Stefan problem with mixed bc

I am trying to solve through Mathematica the classical Stefan problem $$ \left\{ \begin{array}{lll} \dot{v}(x,t)=v_{xx}(x,t) & x\in(0,s(t))\\ \dot{s}(t)=-v_x(s(t),t) & x = s(t)\\ v(0,t) = 0 &...
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0 votes
0 answers
56 views

How to inverse a function?

I have a function:$$D_j\left(\beta_j,B\right)=B\left(\left(\frac{1}{4}-\frac{\beta_j}{B}\right)\left( 1-\left(1- e^{-30\beta_j/B} \right)^8\right)+\frac{2/B}{3+1/B^2}\left(1- e^{-30\beta_j/B} \right)^...
  • 771
0 votes
2 answers
73 views

Plotting natural log equation in 3D plane

I have a natural log equation from excel and I need to plot it on 3D plane at a particular z(for example, z=1) I would expect a vertical plane, but what I am getting is a horizontal plane. This is ...
  • 9
2 votes
2 answers
182 views

Sorting a List Based on a Given Order

Suppose I have the following input: input={{1, 2, 3}, {-2, 4, 6}, {-1, 3, 6}} How can I sort it according to this list: ...
  • 2,293
0 votes
0 answers
23 views

Using HTTPRequest to Obtain an Access Code

I am trying to create a Mathematica equivalent to the following code: ...
  • 307
0 votes
0 answers
30 views

How would I convert AircraftData[] to an Entity[] that could be used with ImageIdentify[]?

I am working on a Design of Experiments to determine the image adjustment settings for a given collection of aircraft images to maximize the probabilities of correctly identifying the aircraft types ...
  • 2,185

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