0
votes
0answers
2 views

Find an instance satisfying an inequality involving sums

Good day. I am new to Mathematica and I am looking for advice. Is it possible to solve $$\sum_{k=0}^{n} \frac{p^k}{k!}>0$$ for $n$ where $p$ is a constant parameter? When I do ...
1
vote
0answers
10 views

Generating Meshes with Conforming Boundaries for FEM

I would like to solve a PDE on an annulus with some boundary condition that relates the inner circle to the outer circle. (For example, periodicity along radial lines). If I use a finite element ...
-3
votes
0answers
16 views

Hold and Release an import

I'm in Manipulate bloc to make a dynamic car selector, but there is a point in which i need to load the car specifications but if I don't hold the import causes an error here is the code ...
0
votes
0answers
16 views

How to deal with Missing[NotFound]

I'm getting the position in array of pick vlue, and always obtain Missing[NotFound] until I select comething, there are any way to ckech if variable is a number and ...
4
votes
0answers
14 views

Export XMLElements with MathML contents

Setup Here's my mathML expression: mathML = ExportString[1/2, "MathML"] ...
1
vote
0answers
14 views

NDSolve : Boundary conditions of lower order

Given the (dummy) problem ...
0
votes
0answers
10 views

Physical interpretation of residues [migrated]

What is physical interpretation of residues of poles (of any order) of a complex function? Poles represents the points where a complex function cease to be analytic and residues are calculated to ...
1
vote
0answers
31 views

Use Solve[] with Bessel, gamma, and hypergeometric functions?

I need to find values of {a,b,c} such that the 0th, 2nd, and 4th order moments of f[x]=Exp[-ax^4 - bx^2 - c] will equal respectively {1,2,10}. I didn't really expect this to work, and it didn't: ...
-4
votes
1answer
40 views

how to change parameters in NDSolve?

I want to solve a PDE with parameters chosen based on the sign of derivative. For instance in the following PDE ...
3
votes
0answers
32 views

A question about weighted graphs [on hold]

I need create a weighted graph with given data. Number of nodes: $53$ $\quad$ Number of edges: $91$ ...
0
votes
0answers
30 views

Huge eps file while exporting

I am using Graphics3D and Sphere command to generate a figure. But, unfortunately when I save it as eps file it's size comes up to be ~400MB. What can I do for reducing it?
0
votes
0answers
27 views

Applying transformations to data coming from an STL file

I am very new with the use of 3D graphics in Mathematica, so my question might be very naive. I need to Import an STL file, apply transformations to it (rotation and translation), and export it back ...
3
votes
2answers
146 views

Storing Variables in “Loops” and Point Plotting

Given the function $y=\sin x$ defined over the region $-\pi \leq x \leq \pi$, I need to implement a "do loop" such that I sweep over 100 or so points $-1 \leq y \leq 1$ and find precisely the two $x$ ...
0
votes
1answer
28 views

The FindRoot output only with numbers [duplicate]

I have this code in Mathematica: FindRoot[{Sin[x - y + 2] - x == 0, Sin[2 x - z] - 8 z == 0, Sin[z + y + z] - 2 x == 0}, {{x, 0}, {y, 0}, {z, 0}}] where it's ...
0
votes
0answers
23 views

How do I make a RNG in a function run only when I call the function? [on hold]

In Mathematica, I've made the following function: ...
1
vote
1answer
45 views

Defining a derivative on a custom function

I am trying to define a derivative that acts on a custom function, $f$, such that when it acts, it increments one of the arguments of by 1. f is not defined; I just want to use it to keep track of ...
2
votes
3answers
97 views

Find position avoiding For loop

I have a list: {a,b,c,d,e,f} And a function sizeFunc[element_] which returns the size ...
5
votes
0answers
45 views

How does Dataset compare to DataFrame in pandas?

Pandas is a Python package providing fast, flexible, and expressive data structures designed to make working with “relational” or “labeled” data. Just like ...
1
vote
1answer
28 views

NumberLinePlot: How to make the 3rd list (c) appears with “black crosses” or “void circles”?

a = {1, 2, 5, 2} b = {2} c = {1.75, 2.88, 3.25} NumberLinePlot[{a, b, c}, PlotStyle -> Directive[PointSize[0.032]]] I thought about PlotMarkers or PlotStyle, ...
1
vote
2answers
78 views

Plotting a function with implicitly defined variable

I have a question about plotting a function with an implicitly defined variable. I think the solution should be something similar like here: Define a function with variables linked implicitly but I ...
1
vote
1answer
35 views

Plotting function in cylindrical coordinates (r,theta,z) [duplicate]

I have a function of two variables (r,theta), and I would like to plot it as a surface using cylindrical coordinates. Based on my research, there is no built mathematica function for plotting ...
0
votes
0answers
6 views

Can these steps be converted to a mathematical expression using equations/graph theory/Calculus/Set theory/functions/? [migrated]

Want to convert below algorithm into a mathematical model:- General points 1. Let there be a Connected Directed Graph. G = (V, E) V vertices or nodes E edges. This graph can be seen as a network ...
2
votes
1answer
38 views

Dropping rational coefficients

I have a list of expressions (they all are exact numeric quantities, not containing any variables), some of them have integer or rationals coefficients, or complex coefficients with rational or ...
1
vote
2answers
57 views

Trouble simplifying using Replace

I have the following expression: w.a.b.r+w.c.d.r I want to get: w.(a.b+c.d).r So far I used ReplaceRepeated: ...
0
votes
1answer
52 views

Sum with 2 different variables

I want to plot Contour or Streamplot a function with a sum. The first part (Abs[v/u]>1) looks like this: $L(u,v)=\sum_{s=0}^\infty \frac{(-1)^s}{2s+1} ...
2
votes
2answers
61 views

Gauss Fit to List of 2D Points

I've been trying to find a solution to what I think is a common problem. I have a list of Data like ...
0
votes
1answer
28 views

How to select components selected via SelectComponents?

I have selected the components of a "reduced" (dilated, thinned) image, now I need to go back to the original image and find the coordinates of the components I have found. My code currently does ...
1
vote
0answers
27 views

Accessing the elements of a list of values [on hold]

I have a list of polynomials (all with the variable x) called lyle and a function that accesses this list and evaluates it at ...
3
votes
1answer
167 views

Decode a text which is encoded with UTF-8

I would like to decode a text which is encode with UTF-8. My code is here : ...
3
votes
2answers
180 views

Implementing Picard's Iteration for solving ODEs

Picard's Iteration is a way of solving the IVP $$y'(x)=f(x,y(x)), \quad y(x_0)=y_0 $$ It consists of defining the following sequence of functions recursively: $$y_0(x):=y_0 \\ ...
4
votes
2answers
480 views

Order of a pole

Is there a simple way to determine the order of the poles of a rational function? I have a difficult function where I need Mathematica to find the poles. It would be interesting to also know what the ...
1
vote
0answers
14 views

How to change the MaxIterations option in the neural network method of the predict command

The neural network method of the predict command seems to support a number of undocumented options as shown in a previous question [1]: How to change NeuralNetwork options? Did anybody already have ...
1
vote
1answer
31 views

Use e notation in Stream output [on hold]

I'm trying to save the results of a huge Radia calculation. I evaluate the function in a loop at multiple locations. To export the data my first approach was to fill a Table and use the ...
0
votes
0answers
46 views

The graph of a piecewise function [on hold]

Let $$f(x)=\begin{cases} n,\quad\text{if }\quad n<x<n+\frac{1}{n^3}, \\ 0,\quad\text{if }\quad n+\frac{1}{n^3}\leq x\leq n+1 , \end{cases}$$ Using mathematica, I attempted to draw the graph ...
0
votes
0answers
46 views

How to make the plot smooth

There are some stranges point which cause the figure isn't smooth. I think that the reason is the method of numericial integration. Here is my code, it's pleasure that one can revise the drawbacks in ...
1
vote
0answers
29 views

How to avoid import evaluation until if wil return true

My goal is to import a data from url that depends of 1 parameter, this initialy value is null or undifined en yo have to selec some popup and then the variable has value, what is the method to do ...
0
votes
1answer
38 views

Pure “Select” function over matrix

I have several lists of tuples in the following shape: l1 = {{1, 134}, {2, 314}, {3, 164}} I do want to select, from each list, list elements fulfilling a ...
0
votes
0answers
3 views

Max/Min to logical operator trasformation and viceversa [migrated]

I have some doubts in trasforming conditions that involves max/min in logical operator condition and viceversa. In particular, should be (I put some examples, I would know if I'm right and the ...
0
votes
1answer
29 views

Finding solution of equation with differentials [on hold]

I am trying to find the point of maximum exponential curvature, where the exponent equation is: y = 0.2e^(0.4x) I know the equation for this point is: k = y'' / [(1+y')²]^(3/2) How can I code this ...
0
votes
0answers
38 views

PDE: Inconsistent equation dimensions

EDIT: I need to solve the following PDE: $\nabla^2\vec{A}=-\mu_{0}\vec{j}$ where $\vec{j}=\sigma\vec{E}$ and $\sigma=1*10^{10}$ which basically boils down to three different PDE's; ...
1
vote
1answer
41 views

How to apply Simplify only to elements of list that cause specific Warning

I have a set of replacement rules I use to analytically compute nested integrals of very long symbolic expressions since Integrate literally takes forever. To do ...
1
vote
1answer
27 views

Pulling out a prefactor from a dot product [on hold]

I have three complicated vectors u, v and w as well as three simple prefactors ...
0
votes
0answers
22 views

General formula for total derivative [on hold]

I have a real-valued function $f\{x, y(x)\}$, with $x,y\in\mathbb R$. I would like to compute the total derivative with respect to $x$ in Mathematica. However, I am not able to write exactly that ...
0
votes
3answers
35 views

Generating a large table of values and selecting some of them following some condition

I am working on a problem where I have to generate a table of components while each component of the table has 18 entries. Six of the indices among 18 run from 0 to 1 while the other 12 can take ...
2
votes
3answers
212 views

Help with PatternSequence

I have a list of strings of the form list = {str1, str2, strx, str3, .., str10} each string contains both letters and numbers, except for ...
-1
votes
0answers
41 views

Can I get a closed form solution using Mathematica symbolically? [on hold]

I am working on nonlinear equations for my research. I need to use some software to get a closed form solution of the systems of nonlinear equations. Here is just an example: If I want to get a ...
3
votes
1answer
63 views

FindFormula can't deal with the population data from Wolfram server

In the documentation of FindFormula, the first application of it is to predict the population of Poland. ...
-1
votes
0answers
15 views

How to fit a 3-parameter logistic model by R and GLM [on hold]

I have a model follow a 3-parameter logistic model like: $E(Y|x;\beta)=\frac{\beta_2}{1+exp\{(\beta_1-log_2x)/\beta_0\}}$ How can I use GLM to fit this model in R?
2
votes
1answer
119 views

Plot not working for a phase diagram

Whatever I have tried, I could not achieve to plot numerical values coming from my system of differential equation. It is a optimal control model with two state variables. My differential system is ...

15 30 50 per page