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5answers
80 views

How to prove the inequality $abc(a+b+c)^2≤(a^3+b^3+c^3)(ab+bc+ca)$? [closed]

I need to prove something like that: For a,b,c>0 prove: $abc(a+b+c)^2≤(a^3+b^3+c^3)(ab+bc+ca)$. I know that $3abc≤(a^3+b^3+c^3)$, but then I derived $3(ab+bc+ca) ≤ (a+b+c)^2$, I can't move on. Can ...
0
votes
1answer
34 views

Frame around text or MaTeX? [duplicate]

This seems like it should be easy, but I can't figure out how to do it or any documentation of it. How does one add a frame (not an outline, but a frame) around Text...
2
votes
2answers
49 views

Using a list inside NDSolve

I have a coupled differential eqations: ...
8
votes
2answers
168 views

Why Mathematica gives wrong eigenvalues for this equation?

Here is an eigenvalue problem in cylindrical coordinate: $$\mu(r)\frac{\partial}{\partial r} \left( \frac{1}{\mu(r)}\frac{1}{r}\frac{\partial (ru)}{\partial r} \right)=-p^2u$$ where p is the required ...
0
votes
0answers
21 views

Doubt regarding the creation of a symbolic 2nd rank symmetric tensor in Mathematica

I would like to ask the following: In a previous post it was asked how to create a 2nd-order symbolic tensor in Mathematica. Given the following notation ...
4
votes
1answer
191 views

Continued fraction expansion of a rational function

Maybe I'm missing something, but what would be a good way to calculate the continued fraction expansion of a rational function $Z(s) = N(s)/D(s)$? The built-in function ...
10
votes
1answer
159 views

How can I ingest and analyze benchmark results posted at MSE?

How can I ingest Mathematica / WL benchmark results posted at Mathematica Stack Exchange (MSE), like the ones posted here? Assumptions: There are multiple answers with benchmarks posted The ...
2
votes
1answer
155 views

Fitting model to data

I have been trying to adapt some of the previous suggestions on other questions similar to my problem but I haven´t been able to solve my problem so far. Best wishes
5
votes
11answers
302 views

Benchmarking with Mathematica v.12 for up to date comparison across different machines

I am planning to purchase a new computer especially to use for Mathematica programming purposes. Currently, I have MMA v.11. Could someone with Mathematica v.12 run the following benchmarking and ...
0
votes
1answer
66 views

How do I see output for intermediate steps in a program? [closed]

I understand Mathematica programs to be a series of steps enclosed in simple parentheses. Each 'step' ends in a semicolon except for the last. The program output is then the output of the last step ...
0
votes
1answer
41 views

Memoization Involving More than one Variable [duplicate]

Good morning. I would like to know if there is a way to implement memoization if there is more than one variable involved in the memoization; or more accurately, for my problem, have the memoization ...
3
votes
2answers
37 views

Changing axes units

I have plotted a graph in mathematica, where the x axis is in seconds. I want to scale the axis so it displays years instead. My plotting function is as follows: ...
1
vote
2answers
28 views

How to help Simplify with conjugates without using ComplexExpand

I have a seemingly simple simplification involving conjugates: $Assumptions = Element[{a}, Reals]; FullSimplify[ x E^(I a) + Conjugate[x] E^(-I a)] which merely ...
5
votes
1answer
35 views

Plotting regions with 1D and 2D components

I am trying to plot a region defined by an inequality which contains both a 2D square and a 1D segment. My issue is that RegionPlot only shows the square and ignores the line. I noticed that if I use ...
0
votes
1answer
183 views

Creating a numerical table of values and using an interpolation of them to transform pixels in an image by the ImageTransformation command

I am trying to carry out point "Implementing Map" on this paper Interstellar wormholes however I am using my own equations not those given (only the same method). I have generated a list of ...
5
votes
2answers
957 views

Mathematica Interpolation or approximation

I have lists of points X and Y. {1212,1216,1217,1219...}, {1,2,3,4,5,6...} I combine ...
5
votes
3answers
181 views

Plotting a normal curve over a histogram

I am teaching a basic introduction to normal curves, and the textbook introduces the topic with the idea of rolling five dice and recording the sum. Do this many times and create a histogram of the ...
5
votes
3answers
340 views

Curve Fitting Data using Polynomial

I have this data set in Mathematica: ...
1
vote
1answer
33 views

Understanding and visualizing Bessel function with complex argument

I have a vector field in polar coordinates $(r,\phi)$, which I wish to visualize and better understand. It represents the Electric field vectors for a given field distribution inside a circular ...
0
votes
1answer
32 views

Having problem in solving 11x11 symmetric matrix in mathematica

I am solving an 11x11 matrix in Mathematica. I am facing problem when I try to find the determinant or eigenvalues of this matrix. The error generated shows that the matrix is not square therefore it ...
7
votes
3answers
385 views

How can I sketch a right-angled triangle?

I would like to replicate this ellipse, but with a right-angled triangle (with smooth/rounded corners). The formula for this ellipse: ...
0
votes
1answer
87 views

Transforming a full $4\times4$ symbolic matrix into a full $3\times3$ matrix and an eigenvalue

I have a $4\times4$ matrix A=\begin{pmatrix} 0.16 (\cos (\text{kx})+2) & 0.55 \cos \left(\frac{\text{kx}}{2}\right)+(0.\, +0.76 i) \sin \left(\frac{\text{kx}}{2}\right) & 0.55 \cos \left(\...
11
votes
3answers
5k views

Use Alpha Vantage as an alternative to Yahoo FinancialData, and how to use financial indicators on these data

Alpha Vantage Inc. is a leading provider of free APIs in JSON and CSV formats for real-time and historical stock market data. With the recent glitch of the Yahoo Finance API, and with ...
2
votes
1answer
55 views

How to turn on all suppressed error messages

I have a variety of possible errors in each iteration of a for loop. If, in one iteration of the loop, there are more than 3 error messages of the same kind, I am happy that the rest are suppressed. ...
3
votes
0answers
31 views

Mathematica refuses to output ContourIntegral and DoubleContourIntegral in nice mathmatical Notation

I experience a strange behaviour of handling the Contour and Double Contour Integral symbols \[ContourIntegral] and \[DoubleContourIntegral] in Mathematica. Whatever I try theyy behave differently ...
2
votes
0answers
75 views

Will the new compiler give access to pointer arithmetic like that done in C?

I was watching this video and came across the Handle type construct in the new compiler. So my question is the new Handle[...] ...
2
votes
0answers
38 views

Trigonometric Simplification and Double Angle Formula

I am trying to achieve the formula hbar / 2 * cos(wt) * sin(theta). However, my Mathematica expression doesn't seem to simplify the half/double angle formulas. I am ...
7
votes
2answers
112 views
+200

InputField with carriage return in cloud notebooks?

I'm looking for a way of constructing a multi-line InputField in a cloud notebook. That is, a text field that supports the following five behaviors: The 'Enter' ...
2
votes
2answers
39 views

Let NCAlgebra know that Tr[] commutes

I have an expression where there are terms like a ** (b*Tr[a ** b]) and I want to simplify it to something like ...
1
vote
0answers
49 views

is the Fox-Wright Psi solution of the trinomial equation implemented in mathematica?

According to (13.4) in Belkic: the trinomial roots, their powers and logarithms from the Lambert series, Bell polynomials and Fox–Wright function https://d-nb.info/1176090631/34 the solution of ...
2
votes
2answers
58 views

Plot legend for filling

I have a plot where several lines and curves intersect, and the regions between them are filled with red and blue. My code is ...
3
votes
4answers
96 views

3D Tube with large disparity in point magnitudes

Consider a tube in 3D, where one of the dimensions is much flatter than the others: pts = Table[{i, i, i/100.0}, {i, 1, 100}]; Graphics3D[Tube[pts]] This is fine,...
0
votes
0answers
22 views

How to export a list of names from excel to an array [closed]

I have a table in Excel with one column like this: 123 124 167 273 Now, I would like to turn this into the text in the form: "123","124","167","273" That is: &...
2
votes
0answers
29 views

Need to determine turn in Connect Four based on mouse clicks (Mathematica)

I am making a connect four game and I need to figure out which graphic to use (red or black) by how many times the mouse has been clicked. So I need a counter for mouse clicks. That way I can make an ...
4
votes
2answers
141 views

How to import a COVID-19 data table from a website into a Mathematica notebook

This link https://www.worldometers.info/coronavirus/ provides daily cases of COVID-19 across all the countries. Is there an easy way to retrieve this table into a Mathematica notebook? I tried: ...
1
vote
2answers
63 views

Semi-direct product and crossed product symbols

Does Mathematica have any symbols for the semi-direct product $\rtimes$ (or $\ltimes$) and the crossed product $\bowtie$? I have looked at the lists containing all symbols and couldn't find it there. ...
0
votes
0answers
13 views

How to reverse or restore the order of my cells in Wolfram Mathematica Cloud?

I was completing my assignment and I have no idea what I clicked but all the cells got reversed that is the 1st one on the last and the last is the first cell in my file. I want to restore it back. I ...
3
votes
1answer
286 views
+50

Limited Opacity Levels in Image3D?

I'm trying to render a simple spherical distribution where the opacity varies with radius using Image3D. Unfortunately, the outcome is not very appealing, with ...
4
votes
1answer
43 views

Invert Selection checkbox

I want to use a checkbox to invert the current checkboxbar selection, the code now basically works, but I hope that when the checkboxbar is all selected or not, the status of the first checkbox will ...
0
votes
1answer
45 views

Testing a condition to replace elements of amatrix [closed]

I want to write a code that checks each element of a given matrix C2 and in case they are't 0 or 1 , replaces them with 1. My code is so far as follows and the code ...
7
votes
3answers
73 views

Make an InterpolatingFunction periodic

Interpolation can make an InterpolatingFunction periodic with the option ...
0
votes
1answer
132 views
+50

Plot of the derivative of a function

I have a function functionSL as a function of t (t<0) where I want to find the extremum ...
1
vote
2answers
102 views

ParametricPlot3D as a ContourPlot

I want to plot the amplitude of a complex-valued function of one complex variable. I want to do this in the plane defined by the real and imaginary parts of the complex variable as a ...
2
votes
0answers
26 views

Trouble with ParametricPlot and custom options

Consider the following code: Options[pl] = {lim->{0,1}}; pl[n_, OptionsPattern[]] := Plot[x^n, Join[{x}, OptionValue[lim]] ] This function works as expected on ...
0
votes
0answers
26 views

Matrix as the discretization of a function $u$ over a rectangle in 3D, how to integrate fast along the axes

I have a function $u$ from 3D to 1D approximated in a list uu and I want to calculate e.g. $$\int_0^1 x\cdot u(x,y,z)dx$$ or $$\int_0^1\int_0^1\int_0^1 u(x,y,z)...
2
votes
1answer
32 views

alternate coordinate repetition from the list

The output of this code repeats every x coordinate except last node. But I want to print the coordinate in such a way that coordinate at every odd position should be repeated except last node. ...
0
votes
0answers
20 views

How To Define An Outer Product (in xAct)?

I am working with xAct / xCoba / xTras and I would like to construct a matrix out of a vector. So, I have a vector V on a manifold ...
14
votes
4answers
442 views
+150

NDSolve giving a wrong solution

Consider the ODE $$\frac{y'y}{1+\frac{1}{2} \sqrt{1+ y'^2}}=-x.$$ Using NDSolve[{-x==y'[x] y[x]/(1+Sqrt[1+(y'[x])^2]/2), y[0] ==3}, y, {x,-7,7}] and plotting leads ...
1
vote
0answers
43 views

Want neural net example of rules {vector->string}

I am using data samples from a multispectral color sensor for color classification as an exercise in beginning to learn about neural networks. I have succeeded with ...
5
votes
6answers
115 views

Highlight elements in the list using pattern matching

Starting from the following list: list = {{a, b, c}, {d, e, f}, {g, h, i}, {b, c, d}, {c, a, m}, {c, d, n}}; I want to ...

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