# All Questions

57,893 questions
102 views

### Multivariate Newton-Raphson method and FindRoot module [on hold]

Let's suppose that we have the following equation ...
48 views

### Why the solution is having a negative value, it should be positive as it is a physical quantity

I want to solve 5 non-linear equations simultaneously, so I am using Solve[] function. Here is my code: ...
43 views

### Why does Mathematica indent comments the way it does?

Whenever I type multi-line comments in Mathematica, the standard editor automatically performs indentation. I find the indentation rather curious and annoying, with some example frustrations posted ...
27 views

### Help with weird behaviour of Map[Take… on large lists

Lets say I create a giant list: tmp=RandomReal[{1,10},600000000]; Now I want to take 10 random sublists of length 150000: ...
588 views

### How do I use low level FEM?

How do I simulate the following partial differential equation using Low level FEM in Mathematica? D[u[x,y], x] - D[u[x,y], y] = x Sin[x y] - y Sin[x y] The ...
61 views

### The set of polynomials under the action by a symmetric group

Let $$f(x_1,x_2,x_3)=\frac{x_1^r x_2^r \left(1-x_1 x_3\right) \left(1-x_2 x_3\right)}{\left(1-\frac{x_2}{x_1}\right) \left(1-\frac{x_3}{x_1}\right)\left(1-\frac{x_3}{x_2}\right)},$$ where $r$ is a ...
35 views

### Collecting w.r.t. long expression

Sorry for a probably naive question. I have the following expression ...
136 views

### Removing anomalous points from data

I have two sets of 2d-data points which can be transformed in each other by using a certain transformation function. The problem is that in both data sets there are points which do not have ...
26 views

### Add to the ODE solution at some timestep

I have two ODE: ...
40 views

### Integrating Logarithms [closed]

I am having trouble to understand why these two lines give different answers. ...
71 views

### How can I plot this integral?

I am in the following situation: I have a complicated ODE for the function f[x] that has no anlytical solution and an integral that depends on ...
30 views

### Create library of custom functions [duplicate]

I have been trying to create a library of custom functions that I could just call at the start of every notebook. For instance, say I want the following functions to be part of the Library, or even ...
36 views

### On the variables used by ForAll

I have the following system of inequalities: test = (1+a>=b)&&(a>=0)&&(1+a+b>=0) So if I use the following code: ...
48 views

### Fitting data using a parametric differential equation

I was fit the data using differential equation(eqns) and pfun I tried data fitting (I gave the parameter directly..a=22500, b=10^-22, c=2*10^-40 and scaling factor k=1.04 10^-36) ...
27 views

### ColorFunction in SphericalPlot3D fails with ImageValue

I would like to texture and deform a sphere with with images using various mapping functions between x,y and phi,theta. I figure I should start with $f(phi,theta)=(x,y)$ as a test case. However, I ...
99 views

### Is there any way that convert entire mathematica code to java or python?

I am novice to Mathematica. I want to convert Mathematica code from my textbook to Java or Python to trace coding.
767 views

### Checking whether a certain number is prime

Using the primality test on this site, I found that the concatenation of the digit reversal of the first 548 odd primes in the reverse order is a prime!. It is only a 1998-digit prime, but it took ...
44 views

### Creating Voronoi Mesh Region Bounded by Convex Hull (Possible problem with DiscretizeGraphics)

I want to create a MeshRegion that is VoronoiMesh bounded by the associated ConvexHullMesh. I followed the procedure in the answer for this post, but the resulting MeshRegion is very wrong. This is ...
134 views

### Does Mathematica gives us a wrong result for the integral of a function including elliptic functions?

Calculus tells us that the differentiation of the integral of a function should be itself, but at least in one case Mathematica answers NO. I feel very confused. The new figure seems to bifurcate at ...
112 views

### Another way to calculate frequency from Fourier transform

I have some trouble with calculating frequency after Fourier transform. My code: ...
65 views

### Creating a nested table

I have a row of values that I partition into a table. row = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}; rowPartitioned = Partition[row, 6] ...
37 views

### PDE solution of the form F[x1,x2][x3,x4]

I am trying to solve a PDE on Mathematica and the solution has the form F[x1,x2][x3,x4]. How do you interpret this function in mathematical terms?
64 views

### NMaximize not solving my problem

Check the following, integer problem: ...
47 views

### Generate a table for the percentage of even numbers in Sierpinsky triangle?

I have this question on the Sierpinski Triangle: What percentage of the figure is blue? ...
23 views

### Keep math variable size consistent when copying to text cell [on hold]

When I type in a math cell, the text of any given variable or operator can remain constant (in my case, 13 pt) but if I try to type equations into my text cell (for analysis/discussion) it scales the ...
41 views

### Rule based list manipulation

I'm trying to restructure the following expression: start = Table[{1, 2, 3, 4}, 5]; Join[{ToString /@ {first, second, third, fourth}},start] Into this: ...
63 views

### Does the position of a comment in a CompoundExpression matter for the result obtained with Out (%)?

I would like to understand what happens when we include a comment at the end of a line that ends with a semicolon. For example, if you execute ...
104 views

### Sum a certain hypergeometric-function-based expression pertaining to an integration problem

I would like to sum over the index $h$ from 3 to $\infty$, the expression ...
59 views

### Manipulation of two lists of strings and integers

I have the following lists: ...
310 views

### Unexpected behaviour of Nothing inside List inside Association

When evaluating the following input: <|a -> {c, d, e}|> /. d -> Nothing I get (expression 1): ...
80 views

### Plot a Mathieu stability chart

I'm working with the Mathieu equation as a part of my research and as part of the analysis I'd like to include a stability chart such as Fig. 1 in this paper. Unfortunately I'm stuck with Mathematica ...
39 views

### Ranking polynomials based on global maxima

Suppose I have the following polynomials in an association i.e. <|...|>, they are: ...
82 views

### HoldFirst being overridden by Activate

So here's the problem a=1;a=2 works because of the HoldFirst attribute of Set, so that it ...
83 views

### Problem with the Inverse CDF of Non-central F Ratio Distribution

In[3]:= n = 5; n1 = 4; n2 = 6; γ = 0.05; α = 1/370; InverseCDF[NoncentralFRatioDistribution[1, n1 - 1, n1/γ^2], 1 - α - (n - n1)/n2] During evaluation of In[3]...
97 views

### NDsolve with ODE-PDE

Kindly I hope to know what is the wrong here. How to use NDsolve for a coupled ODE-PDE differential equations ...
65 views

32 views

### How to extract argument of MeshRegion-Object? [duplicate]

Consider examplary a MeshRegion-Object test = MeshRegion[{{0, 0}, {1, 0}, {2,1/2}, {2, -1/2}}, {Line[{1, 2}], Line[{2, 3}],Line[{3, 4}],Line[{4, 2}]}]; Looking ...
27 views

### Change the dimension of the result of PointLegend? [duplicate]

Here is the output of PointLegend: ...
46 views

### Finding the inverse of a function

I am to solve for $r(\rho)$ given the function, \[Rho]Asymp[r_,b_,q_] := 1/(1 - q) Gamma[1/(1 - q)]/Gamma[(q - 2)/(q - 1)] r Sqrt[1 - (b/r)^(1 - q)] This can be ...
54 views

### ParametricNDSolve[] for Double Damped Pendulum

I am trying to plot Driven Double Pendulum with a control Parameter "Gamma". My understanding is that as this gamma approaches a critical value, the pendulum is pushed towards non-linear regime, and ...
34 views

### Numerical solution to approximate the singular integration using collocation method

I am working to solve "numerically" the following integral equation IE: u[x]=f[x]+Integrate[(1/(x-t)^(1/4))*u[t],{t,0,x}]+Integrate[(1/(x-t)^(1/4))*u[t],{t,0,1}] ...
42 views

### How to take a point randomly from a region [duplicate]

I want to take some points randomly by the limits above, I had try to use FindInstance method but it always out (0,0) ...
39 views

### Mathematica stuck at running symbolic multidimensional Fourier Transform

I'm trying to compute the analytical FT of a bidimensional exponential decay as follows: $f_E(\vec{x}) = \exp \left( - \sqrt{ (\vec{x} - \vec{\mu})^T \Sigma^{-1} (\vec{x} - \vec{\mu}) } \right)$ ...
36 views

### Adding color and opacity to 2D scalar function with respect to its abolute value?

I'm trying to represent the absolute density of a 2-variable scalar function by color and tranparency/opacity. By absolute denstiy, I mean the absolute function value. I tried to do the coloring as ...
65 views

### Is there any way to align both codes and comments?

a=4; (*length*) b=5; (*width*) s=a*b; (*area*) Is there any way to align the code above left and also align the comments? Now it looks ...
18 views

### How to set parameters for CUDAFunctionLoad for a CUDA kernel?

I am trying to load the following CUDA kernel using CUDAFunctionLoad: ...
49 views

### Using list of rules from imported .mat file

I'm attempting to learn Mathematica to replace MATLAB. However, I have some data in .mat files which contains named variables. Whenever I import the .mat file, I get a list of rules. What's the best ...
31 views

### Coloring ParametricPlot of several complex functions

I want to PlotLegends -> "Expressions" for G with different colors where G = {{Sqrt[1 - x] + I Sqrt[x]}, {Sqrt[1 - x] - I Sqrt[x]}} I tried the following ...
I'm solving Laplace equation $\nabla^2 \phi = 0$ with BC's $\phi_x(x=\pm 1) = 0,\, \phi_y(y=-h) = 0$ with a specified BC along the circular arc $x^2 + (-1 + y)^2 = 4$, which I call $\Gamma$ (so the ...