# All Questions

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51 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(\...
59 views

### Is this the weakness or the strength of Mathematica?

I really love the flexibility of Mathematica: there are several ways to perform one task. However, to get the performance of the intense numeric calculation, it can ...
19 views

### Classify; how UtilityFunction matrix is applied to resolve prediction?

I can't find any explanation about the details of the real computation, please anybody knows? ...
141 views

### Dynamic filling of a region of a polar plot

I would like to shade area of region as a function of angle using PolarPlot. Here is my attempt. ...
19 views

### non-linear model fit function not working

I have attempted to exercise a non-linear model fit to my data, dadtAbs, and got the following puzzle ...
72 views

### Unexpected results from NonlinearModelFit [closed]

I have attempted to exercise a non-linear model fit to my data, dadtAbs, and got the following puzzle ...
100 views

### Fitting a two-dimensional Gaussian to the image

I have a image which I want to fit 2d Gaussian function with that. I used the below codes but the output figure doesn't look alright. I extracted the mean and covariance values in x and y direction.I ...
68 views

### Using iterative functions to specifically sort a list

The following code sort the list li in a such way that consecutive terms $t_n,t_{n+1}$ are of the from ...{x_,y_}, {y_,z_}.... i....
49 views

### How Do I fill the Area of a Polar Plot

Grandson and I are working on the Calculus of Polar Coordinates, specifically, finding the area enclosed by a polar plot. We can find the area; however, we cannot seem to find anything in the ...
54 views

### NDEigensystem to solve differential equation

When trying to solve the differential equation radialEqdouble[k_] = f''[u] + k*u^2*f[u] - u^4*f[u] where k is a constant, I am able to produce a plot consistent ...
22 views

### Natural language programming: identifying a named-entity based on class and context

I am playing with Natural language programming in Mathematica, and can't figure out how to extract the entity classes (i.e. male, female) for the following example text: "This was a pleasant ...
20 views

### How to fix a ParametricNDSolveValue? - Encountered non-numerical value for a derivative at t == 0

How to fix a ParametricNDSolveValue? - "ParametricNDSolveValue::ndnum: Encountered non-numerical value for a derivative at t == 0." I have tried ...
99 views

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### Numerical integrating regions to avoid oscillations

Lets define the functions osc = E^(-((I (4 x^2 - 4 y^2))/(4 \[Pi]))); const = 1/4 Sech[1/2 (-x - y)]^2 Sech[(x - y)/2]^2 Sinh[x]^2; the ...
53 views

### NonlinearModelFit and FindFit not Working

I have a function, not very complicated, somewhat similar to an infinite, converging Geometric Progression. Here is my function: Y = n^t / t!. Nonlinear Model Fit works not at all with this expression....
22 views

### Distinguishing function calls from multiplication when importing LaTeX via ToExpression and TeXForm

I'm trying to parse a LaTeX representation of a Desmos calculator (like this one) via Mathematica. Desmos exposes a JSON representation of its calculators, including a LaTeX representation of ...
52 views
+50

### How to get colors at points in Graphics3D?

To get the color at a 2D point in Graphics you can Rasterize it and look up the pixel value, but not for ...
63 views

### How do I construct a matrix using table command. I can not form it's function

I have to form a matrix like this. How ever I can not directly input. I have to form a function and then use the table command. I am stuck. {{2,5,10},{9,12,17},{28,31,36}}
18 views

### Uncertain behaviour when using FullSimplify

While doing some (symbolic) calculations with Mathematica, I encountered a small problem with the FullSimpilify function that hopefully someone here might explain to me. More specifically, I fear that ...
15 views

### How do I find the solution to a system of 4 variables using the For statement [closed]

I want to use a solve statement inside a for sentence to solve a system, not a single equation
49 views

### Do not evaluate function composition in total derivative

How to achieve that Dt[] does not touch certain function compositions, but still applies all the other derivative transformations. Example: ...
44 views

### Any output with Solve

I am trying to solve a 3 unknowns 3 equations system. The code does not give any error but gives any output neither. ...
676 views

### Making a rectangular label for RegionPlot

I have a plot that includes a RegionPlot. I want to make a rectangle with the same shading as in the region plot to show as a legend. The dumb way I can think off ...
27 views

### How can conditional expressions be used in calculations?

I have a fairly simple system whose solution involves conditional expressions. The system is ...
52 views

### ParametricNDSolveValue - Acid-Base equilibrium kinetics

So Im trying to model the concentration profile of a diffusing species into a sphere in an acid-base equilibrium system. Although im getting a solution, Its not the values or the trends I expect. Is ...
48 views

### How to change DataRange independently for various lists in same plot

I am plotting three lists of different size on the same plot. I want the plot to start from zero rather than 1 on the x-axis. In the past, I have used ...
85 views

### How to move point to front of an axis

I'm trying to create an animation of derivative. My problem is very simple: a point is hidden behind the x-axis. This is my code: ...