13
votes
2answers
232 views
+50

Transform an expression to remove the singularity

I have the expression Sin[c x]/c. Clearly it is undefined at $c=0$, but that is merely a removable singularity, since $$\frac{\sin(cx)}c=x\frac{\sin(cx)}{cx}= ...
2
votes
2answers
143 views

Gradient in a plotstyle

I'm trying to replicate the figure below. Now a nice first approach to do this is by using Mathematica, by making some kind of contourplot with circles and just add a gradient to the contourstyle. Now ...
12
votes
1answer
144 views

Regime Change Stochastic Process

I would like to simulate an Ito process in which the drift and diffusion terms change after hitting a boundary for the first time. For example, a Geometric Brownian Motion X which has 0 drift and ...
1
vote
1answer
43 views

How to reduce trigonometric expressions under special conditions

For the following problems I used "FullSimplify" and "TrigReduce" but I manage to reduce more ...
2
votes
1answer
46 views

Transformation syntax with shortcuts to a more explicit syntax for an equation

I would like to write the following code line without the signs @#%^&*?! Sequence @@ (XMLNote[#1, m] &) /@ attributes I have made this code but it seems ...
0
votes
1answer
101 views

Replacement of terms/Pattern matching involving products of derivatives of a function

In delving into Ramanujan summation, I'm trying to get a hold of the relations of the form $$\sum_{n=0}^\infty f(n)=\dfrac{h\frac{d}{dx}}{{\mathrm{e}^{h\frac{d}{dx}}}-1}\int_{0}^\infty ...
7
votes
2answers
1k views

Controlling the 2D $x–y$ aspect ratio of a 3D plot

I have some data representing a nested list, each element being composed of 3 real numbers like ...
1
vote
1answer
54 views

Import a jpeg file and a mov file and display them side by side

I am planning to use Mathematica for a presentation. In one of the slides I need to place a jpeg file side by side to a mov file. ...
2
votes
1answer
100 views

AutoGeneratedPackage Formatting

If you do Ctrl+Shift+o you open an option inspector. And then you can enable ...
4
votes
2answers
131 views

Improve simulation speed using Compile

I have two square matrices, a hermitian matrix h and an unitary matrix v. I am interested in the following function ...
1
vote
2answers
77 views

Why doesn't Plot draw function within prescribed range?

I have a function: TheoreticalFunction[x_] = 2 / Pi * ArcSin[x] And trying to plot its derivative: ...
5
votes
1answer
156 views

Solution to $y = x^x (1-x)^{(1-x)}$ for $x$ [on hold]

Does anyone have any insight to a symbolic Mathematica solution to this equation for $x$ in terms of y? Symbolic of any sort, just not numeric. $$y = x^x (1-x)^{(1-x)}$$
0
votes
0answers
38 views

Create graph K5, delete 2 edges and 2 vertex, create adjacency matrix [duplicate]

I need help about this problem. I should create graph K5, delete 2 edges and 2 vertex from it and from the new graph create adjacency matrix. I have poor knowledge and i don't need anyone to solve the ...
3
votes
3answers
89 views

Using NDSolve within Manipulate

I'm trying to use NDSolve inside manipulate. Specifically, I have a series of differential equations with coefficients, k1, k2, ...
0
votes
1answer
59 views

Creating Matrix,Inverted and Upper Triangulate inside Module

I was trying to fit this into a module but I didn't have any luck. And for some reason it won't Inverse the Matrix. Here's the code: Input: ...
2
votes
2answers
78 views

Partial reload of definitions from package

In order to keep my code modular, I have defined some functions in "Foo.wl" file, which I source with Needs["Foo`"]. When I modify a single function in Foo, I quit ...
0
votes
0answers
40 views

Issue with combining plots using Show [on hold]

I need to combine two plots, but I can't seem to find a proper way! I tried Show, but I just get an error Show::gcomb: Could not combine the graphics objects. ...
21
votes
3answers
3k views
7
votes
2answers
315 views

How to create an adjustable Bézier curve?

I tried to create an adjustable Bézier curve with the following simple code. However the curve didn't show up. What is the problem? Please help. ...
0
votes
0answers
28 views

Recurrence equation [duplicate]

I need to print the first 10 elements from the string which is a solution of a recurrence equation. If there is a 5 in the elements of the string, then that element should not be printed. For ...
0
votes
0answers
100 views

Heuristic Method to create an uniform distribution of points

Introduction I am now trying to program an algorithm to achieve an uniform distribution of points within a space of dimension n. I started working in 2D. The idea is to achieve an uniform ...
3
votes
1answer
1k views

Convolution of two distribution functions

I have two functions; f[x_] = (1/k) Exp[-x/k] ; g[x_] = (1/p) Exp[-x/p] ; How I can convolve them? In Mathematica for convolving two functions we have this ...
6
votes
1answer
864 views

Convolving/integrating problems

Let's say I want to convolve two functions (f and g), a gaussian with a breit-wigner: ...
6
votes
2answers
323 views

Convolve does not get the correct answer

Convolve[Sinc[x], Exp[-x^2], x, X] (* E^-X^2 π *) is obviously false, but why? Any suggestions ?
2
votes
3answers
146 views

Delete rows based on specific periods

I have data (.xlsx format): two columns - data in first column imported as DateObject (dates with specific time), data in second column are numbers (113388.28, 865165.98 etc.). I want to delete the ...
229
votes
23answers
29k views

What are the most common pitfalls awaiting new users?

As you may already know, Mathematica is a wonderful piece of software. However, it has a few characteristics that tend to confuse new (and sometimes not-so-new) users. That can be clearly seen from ...
3
votes
2answers
140 views

Lower branch of Lambert W function in mathematica

I am interested in values of the Lambert W function, which is defined as the solution to the equation $ z = W(z) e^{W(z)} . $ The solution is not, however, single-valued, but branches into two ...
2
votes
1answer
76 views

DeleteVertex in Kpartite graph

How can i make K7,2 graph and how can i delete 2 vertex? Btw, i need to use package -> Combinatorica`; I tried this: ...
1
vote
1answer
50 views

Descending order of Permutations using Select[Tuples[{5, 4, 3, 2, 1}, {3}], OrderedQ]

I was wondering if there is a possible way to still use OrderedQ and get a descending order of permutations: This is Ascending order: ...
6
votes
1answer
72 views

How to define $\operatorname{Mc}$ and $\operatorname{Ms}$ Mathieu functions in terms of MathieuC and MathieuS?

Reading multiple books about Mathieu functions, I always come across notation like $\operatorname{ce}_r(z,q)$, $\operatorname{se}_r(z,q)$ for angular functions and $\operatorname{Ce}_r(z,q)$, ...
0
votes
1answer
54 views

How can I plot the complex formula as follow? [on hold]

I try for this ... I want to see the result like this ...
81
votes
7answers
22k views

Elegant operations on matrix rows and columns

Question The Mathematica tutorial has a section 'Basic Matrix Operations', describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ...
1
vote
1answer
48 views

Delete Edges in Kpartite Graph

I need to make a K7,2 partite graph , with deleting 2 vertices and plus 2 more random edges , and after that my vertices should be green color. I made the graph K7,2 and deleted 2 vertices with this ...
6
votes
2answers
172 views

How to read complicated result from Reduce?

How can I read this Reduce output from Mathematica that I got from solving an inequality? I do not perfectly know when one case in this case analysis is over and ...
15
votes
2answers
417 views

What is the FrontEnd?

Can anyone sort out what the Front-End is, how it is structured and what its relationship to the Kernel is. The FrontEnd is mentioned quite often but elusively avoids to be caught and clearly defined. ...
0
votes
0answers
36 views

Where can I find mathematica documentation about @@@? [duplicate]

For example, to build a rule from 2 lists {a,b,c},{1,2,3},I use : Rule @@@ Transpose[{{a, b, c}, {1, 2, 3}}] : {a -> 1, b -> 2, c -> 3} OK, but how @@@ works ? (Black magic for me) I am using ...
-1
votes
1answer
60 views

Help needed with assignment [on hold]

Can I get some help with this: Write a module which as an input receives two matrices, the first matrix transforms in to the same matrix, but in the new matrix occur absolute values of the first, ...
1
vote
1answer
62 views

How to use ListPlay and PlayRange in Manipulate

The following correctly produces a click sound: ...
0
votes
0answers
27 views

All irreducible factors of a polynomial over $F_{p[x]}$ [on hold]

I am new to Mathematica. Can anyone explain me how to write a program that inputs two integers $n$ and $p$, where $p$ is prime, then returns all irreducible factors of the ...
5
votes
3answers
112 views

Elegant way to drop rest of a string at the occurence of a character

For example, I have a string "ahfiehfke$jfwfjejf0". Is there an elegant way to drop all characters after "$"? I know loop ...
15
votes
0answers
210 views

Compile not correctly initializing a variable defined inside Module

Bug introduced in 8.0 and persisting through 10.1.0 or later In the following example, inside the minimumX's Module, ...
1
vote
4answers
105 views

Drop row if sum of part of row is equal to zero

My problem is the following: Suppose I have a matrix A which looks the following: ...
2
votes
1answer
93 views

Missing zero in the CoefficientList

The following list has a length only 10 (not 11) CoefficientList[Series[ArcTan[x]/(1-x^2),{x,0,10}],x] {0, 1, 0, 2/3, 0, 13/15, 0, 76/105, 0, 263/315} It should ...
6
votes
5answers
7k views

Calling Correct Function for Plotting DiracDelta

I am wondering what is the correct function in Mathematica to plot the true impulse function, better known as the DiracDelta[] function. When using this inside of a ...
5
votes
0answers
82 views

Wrong Limit with LaguerreL

Limit[(n! LaguerreL[n,-1]/(n^(n+1/4)/Sqrt[2]/E^(n-2 Sqrt[n]+1/2))-1) Sqrt[n], n->∞] Mathematica (wrong) output ...
17
votes
4answers
664 views

A bug in Integrate

Integrate[(1 + 16 Tan[2 x - y]^2)/(1 + 4 Tan[2 x - y]^2), {x, 0, 2 π}] Mathematica (wrong) output is (tested under versions 8 and 10.0, took ~ 1 minute of CPU ...
11
votes
3answers
451 views

How can we plot the complex roots of an equation?

If we'd like to display the $n$ roots of a polynomial on the complex plane as points, how can we do this? For example, if we have the equation $x^3 + x^2 + x + 1$, how can we plot the 3 roots as ...
1
vote
3answers
77 views

Use Do to evaluate an expression over two indices $i \ne j$ (over a list of tuples)?

I have an expression of the form: expr1[i_,j_] = Sum[\[Beta][j]*\[Phi][i, j]* C[i] I would like to evaluate this expression over i=1:4, j=1:4 with i!= j. One ...

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