# All Questions

59,249 questions
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### Precision control of double integral with $i\epsilon$ prescription

I have the following double integral: F[\epsilon,\Omega,\sigma] = \iint_{\mathbb{R}^2}\frac{e^{-t^2/2\sigma^2}e^{-T^2/2\sigma^2}}{(t-T-i\epsilon)^2}e^{-i\Omega(t-T)}\,dt\,dT\,. \end{...
39 views

### Nonlinear Model Fit Returning The Same Values For Different Data [closed]

I am trying to use the NonLinearModelFit Function but the outputs for all my data tables are the same. For example DATASD1 and DATA1SD3 are getting the same output for the parameter table and the ...
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### The Text in GeoMarker

In continuation the topics 1 and 2: I had the map "EKB" and I needed to mark some objects. Just for example: AES= TECgas= <...
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### Changing values in a column of a Dataset using a Do loop

I'm trying to use "Do" to change the entries in a column of a dataset using two adjacent columns. When I simply assign i and execute the lin for each value of i, it works but when I enclose it in Do, ...
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### Deleting missing values from a dataset

I wanted to create a dataset of all UFO sightings in April of 2018. The AssociationThread doesn't want to work, because some of the entries are missing value, what ...
108 views

### How to specify non-reflective boundary conditions when NDSolving two coupled first order PDEs?

Due to a lack of fruitful answers after 3 days, this question has been reformulated in a more direct way compared to its first version. Consider the telegraph equation problem expressed as a system ...
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### How can I take the derivative wrt to qx-px? [closed]

I HAVE TO TAKE A DERIVATIVE WRT TO qx-px d/d(qx-px) ie: d/d(qx-px) F(qx-px, py, T) but Mathematica will not allow this even if I try to "trick it " by defining rx=qx-px ANY IDEA HOW i MIGHT TAKE ...
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### BinarySearch Built-in and BinarySearch1 Self defined help [closed]

I am trying to create my own binary search to compare with the built-in function. I have referenced the docs, but the output is not correct and implies an issue. Please help with my function syntax ...
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### Plotting a point beneath the surface of a sphere [on hold]

I'm trying to represent a point beneath the surface of the earth. I can plot coordinates based on latitude and longitude to get a point directly above where it's supposed to be, but now I need the ...
56 views

### Direction of NeumannValue on boundary

When solving partial differential equations NeumannValue is used to specify the flux across the boundary. For normal fluxes the detailed notes state They appear on the boundary ∂Ω of the region Ω ...
59 views

### Giving Plot options defined outside of the Plot expression

How can I give Plot formating expressions on a separate line just like ListPlot? When I use the following code with ...
28 views

### How to resize an input image to make its dimensions [closed]

When using the ImageTransformation command I would like for the input image to be of equal dimensions (as if the image is a square), how could I do this if the ...
24 views

### Error NetTrain::invencin: Invalid input when training a neural network [closed]

I've build a Deep neural network with various variables: ...
47 views

### Looking for integer solutions to an equation [closed]

I want to have code, where I can solve the following equation for whole numbers: $$x^3+y^3+z^3=33\tag1$$ Where $a,y,z$ and $a$ are whole real (positive and negative) numbers. And I want to give ...
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### Plot shows up as blank output line

Let me start by saying this is NOT one of a thousand duplicates of the function not showing up on the plot. Mathematica has been working fine for the last 2 years, and then all of a sudden, ...
94 views

### ToElementMesh of Region with Hole

When I try to mesh the following region it fails. Why? Is there a workaround? ...
34 views

### Problem with {table values} when plotting

I have a Piecewise and Nintegrate both defined with NumericQ. The NIntegrate part of the Piecewise operates when first inserted into a working program, but not when called from inside a table. Their ...
48 views

### I am trying to solve these Chemotaxis Equations but I can't seem to make it work

I am trying to solve a a pair of coupled partial differential equations but it doesn't seem to work. I am getting the error 'Length of the derivative order is not u1[t,x]the same as the number of ...
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### Problem with Z scale density plot color

I have a problem with my Z scale color... I would like to saturate the colors in order to see better the white ring... When I am doing the next line code ...
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### How to maximize just with respect two parameters out of four?

There are some posts explaining how do we maximize a function of two parameters with respect to one of those and how to plot the resulting function: Plot a function after taking the supremum with ...
26 views

### Trouble using ParametricNDSolve in Manipulate

I have troubles to understand how to use Manipulate and ParametricNDSolve to have modulable parameters inside my models. I ...
65 views

### All the group formatting available in Mathematica

I was wondering how many pre-defined group formatting style there is in Mathematica. From Format -> Style, one see that we can go from ...

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