7
votes
1answer
75 views

Expanding derivatives of hypergeometric functions

Sometimes Mathematica expresses results of integration or summation in terms of symbolic derivatives of Hypergeometric2F1 function, and cannot further simplify ...
1
vote
1answer
51 views

Can someone please help me to state assumption?

I am currently trying to solve under what condition does the following term will be zero? ...
0
votes
0answers
56 views

Plotting Geodesics in Kerr

I'm interested in plotting the trajectories of null geodesics near a rotating black hole (given by the Kerr solution) which involves a system of first order differential equations. Some Context (not ...
3
votes
2answers
48 views

Recognizing special cases of a defined function for permuted arguments

I have a number of ugly ways to implement the following pattern recognition task, but I'm looking for something elegant to keep my notebook tidy. I need to define a function of six variables ...
6
votes
4answers
206 views

Conditional Expectation — How can Mathematica find a more general closed form?

Mathematica can't find a solution to this Expectation. ...
2
votes
1answer
69 views

Finding a root of a parameterized integral

I have a function given as a parameterized definite integral: f[a_] := Integrate[BesselJ[0, x - a] BesselJ[0, x + a], {x, -∞, ∞}] I suspect it has a root near ...
3
votes
3answers
84 views

EventHandler Not Detecting KeyDown

I am trying to use EventHandler to detect KeyDown within a LocatorPane. Anytime I press a key inside the LocatorPane the proper action is not executed (doesn't matter which key I choose) but rather ...
3
votes
2answers
131 views

Conversion of 3D plot to 2D Contour Plot

Is it possible for Mathematica to convert a 3D plot into a 2D contour plot without having to recompute the values for each point? I realize that looking directly down at the 3D plot will be similar to ...
1
vote
2answers
58 views

How does one go from a string to the contents of a variable with the same name?

What command should I use if I want to convert a string to the contents of a variable with the same name as the contents of that string withing a function. ToExpression[] doesn't seem to do it. ...
15
votes
7answers
1k views

Is there a way to recreate the typical Red/Blue-Postereffect using Mathematica?

I think nearly all of us have at least once seen an image like this: So I wondered whether it is possible to recreate this effect using Mathematica because it seems like it wouldn't need that many ...
0
votes
0answers
33 views

Let's Make a formula [closed]

Gents, Could you please assist to create a single line MATH formula for: We have numerous 4 element sets. We need to show X sets that are equals to Y. IF m{X} < X then add sets that are equals to ...
0
votes
0answers
11 views

Displaying only unique cell tags OR creating cell group tags

I want to make an extensive use of tags and it would add some clarity if CellGroups could display a tag if all of the cells it has have it. Once the cell group is tagged, the individual cells wouldn't ...
0
votes
0answers
30 views

Expressions to functions, and evaluation [duplicate]

When calculating derivatives a expression is the result: in:= f[x_,y_]:= 1 + 2 x + 3 x^2 y + 4 x y^2 in:= D[f[x,y],x] out= 2 + 6 x y + 4 y^2 how do i make this ...
2
votes
1answer
106 views

How to generate nonperiodic tilings?

I need to generate nonperiodic tilings which are similar to the attached figure (kite-domino tiling). I was thinking the code is similar to the code for the Penrose tiling. However, that code is too ...
0
votes
0answers
64 views

Problems with NMinimize

I have written some functions that take a matrix and find its minimum inner product with a specific set of vectors ...
0
votes
2answers
57 views

Plot a perfect looking circle using two functions, always look like an ellipse [duplicate]

I want to use the the following two functions to plot a perfect looking circle, but the graph always ends up looking a bit squashed. I've been playing with some of the parameters of the function but ...
2
votes
3answers
76 views

How to use this Lorentzian function fit my data, I tried NonlinearModelFit, it always resulted with an error

The data is uploaded to Ideone http://ideone.com/ktIbVk , my code is : ...
0
votes
1answer
59 views

What is wrong with ContourPlot [duplicate]

Why does this plot have a big blank hole in it? ...
-1
votes
1answer
37 views

Take the function f(x)=2x-x^2 and the open interval P=(0,2) why is f(P)=(0,1]? why is that 1 closed? [closed]

I would think it would be f(P)=(0,1). Why does it include the endpoint?
0
votes
0answers
39 views

How to calculate the analytical result of this double integral?

I'm trying to solve this double integral: $I(a,b)=\displaystyle{\int_{-1}^{1}dy\int_1^{\infty } \dfrac{y\left(x^2-1\right) e^{-ax} }{b-\frac{\sqrt{x^2-1}}{x}y} \, dx} \,\, ...
5
votes
5answers
273 views

Populate an upper triangular matrix from a vector of elements

What is the best way to populate an upper triangular (or alternatively: lower triangular or symmetric) matrix from a vector of elements? This example input: ...
0
votes
0answers
71 views

Generate particals in a cube zone: Need code optimizion [closed]

Problem description: Generation different sizes of particals in a cubic zone, of course, that particals must throw one by one in the zone and cannot intersect each other; the particals' coordinates ...
2
votes
1answer
74 views

Aborts and beeps without error warning

I have a piece of code that generates a figure, performing a calculation to generate each pixel. At a certain resolution it runs fine, but after a high enough resolution it fails. Mathematica beeps ...
3
votes
2answers
102 views

Retrieving other information on CountryData

The following input will produce some answers, however how do we find out other details, such as the specific year the result corresponds to, as well as the source from which the data is obtained? ...
0
votes
1answer
44 views

Help with programming(using list) [closed]

I would like to make a program which gives me what is the greater natural number "n" less than an arbitrary given natural number "k" which satisfy: for each prime divisor "p" of n, p^2-1 divides n. I ...
0
votes
0answers
50 views

Replacing variables [closed]

I guess this is a common issue and I tried to search it in this forum. However, I did not find a solution. Suppose I have a function $$f = x + x^2 + x^3$$ I want to replace $x$ as $k x$, namely ...
4
votes
2answers
126 views

Table with multiple iterators running parallel

I want to use Table to generate a list, but it only allows one iterator to increment at a time. So in ...
0
votes
2answers
41 views

Multiply value if it includes a period

I download data from an online source, now I have a problem: the source code doesn't allow to differ between values of 10 (which actually stands for 10) and 10.000 (which is 10'000, but Mathematica ...
4
votes
1answer
188 views
3
votes
3answers
132 views

Multivariate Polynomial Manipulation

I have a large homogenous multivariate polynomial in, say, 5 variables $a,b,c,d,e$. As an example take the polynomial $$a^4+2abcd+a^2 b^2+e^4+cde^2.$$ Now I would like to replace $k$-th power of any ...
0
votes
0answers
28 views

Making a Logplot with errorbars [duplicate]

I have some data points with corresponding error bars. I would like to plot these together with another graph. This other graph is plotted as a LogLinearPlot. I tried plotting the data points by using ...
3
votes
0answers
52 views

Error solving third order ODE in version 10. No error in V9. DSolve`DSolveKovacicDump`

This is an ode which is solved with no error in V9, but gives a very strange error in V10. Is this a regression bug? On version 9, the ode is solved with no error ...
-3
votes
0answers
20 views

Deriving a simple equation to determine score for matched words against search text [closed]

This question is related the one that I asked here. I'm working on a small search algorithm that match objects based on word, tag, last access and frequency. Each matched object has a score that is ...
3
votes
5answers
177 views

Take the next element in a nested list

My problem is the following: Consider a list of elements. To better understanding my following explanations, I would take this example: ...
1
vote
0answers
38 views

Use of Ito's lemma in ItoProcess

In the documentation for the ItoProcess it says: Converting an ItoProcess to standard form automatically makes use of ...
4
votes
0answers
42 views

Connect Frontend to Kernel Started by JVM via JLink

I have a MathKernel started and controlled via JLink from a JVM. The $CommandLine for this kernel is: ...
5
votes
1answer
60 views

Is there any way to automatically evaluate selection in new window or new notebook?

Sometimes when you have long code you need to check some part of this code. the way I am using currently is to selected the part that I want and then copy it to new notebook and then evaluate it ...
4
votes
4answers
267 views

Automatically growing lists as in MATLAB?

Is there a way to add elements to a list at positions outside the current list's length? Something equivalent to the following MATLAB code snippet: ...
7
votes
1answer
196 views

Porting code from MATLAB

I'd like to switch from MATLAB to Mathematica for my research in digital signal processing. I used Mathematica a lot during the '90s but I haven't used it since then, so I might as well be a complete ...
0
votes
0answers
53 views

I see error messages when I use LogLinear Plot but not when I use Plot

I have written an application with Manipulate that plots the results of several calculations. What I find strange is that when I have my application use ...
4
votes
3answers
149 views

How to solve an integral equation by iteration method? [duplicate]

How I can obtain $n^{th}$ approximation of the following equation $f(t)=t+\int_0^tds f(s)$ by iteration method?
2
votes
1answer
87 views

How to input and output partitioned matrices that show partitions and compute as normal?

I want to demonstrate multiplication of partitioned matrices as in the example here. Using the Insert Menu, you can build a matrix and draw lines between rows and columns. However, I want to be able ...
1
vote
0answers
51 views

Solving PDEs with complicated boundary conditions

The system I'm trying to solve is $$\nabla^2 C_{(r,\theta)} =0$$ $$C_{(\infty,\theta)}=C_0$$ $$ [ \frac{\partial C_{(r,\theta)}}{\partial r} \cos(\theta)+\frac{1}{r}\frac{\partial ...
0
votes
3answers
66 views

List of Coefficients of Expression with symbolic Terms

(I am affraid that this is a duplicate, but I read several already asked questions and non of them helped me. If it's already answered, please tell me) I have expressions like this ...
-1
votes
1answer
46 views

Plotting vector field [closed]

I am trying to plot the gradient vector field of the function: $$sin\sqrt{x^2+y^2}$$ This is my code: ...
2
votes
0answers
46 views

Mathlink program with low cpu usage on linux machines only

Question I am incorporating some c++ code via Mathlink into my simulations in Mathematica. My questions involves the execution efficiency of the c++ code on different machines. For example, on my ...
0
votes
1answer
94 views

Making a fit to my empirical data [closed]

I want of plot the fit for the graph The Data for this graph is ...
2
votes
1answer
71 views

ZTest result not making sense

I'm using version 10. I'm having difficulty with understanding why I'm getting some output from the ZTest function. Here is the code for my specific example. ...
0
votes
2answers
53 views

Eigenvectors inside a maniupulate function

I am trying to make a physics application and it requires that the eigenvectors be taken for a 3x3 matrix. It is my intention that Mathematica never have to deal with the matrices symbolically. ...
2
votes
1answer
68 views

How to efficiently process pasted content from PDF

I had selected a matrix in a PDF file, and paste it onto my MMA notebook. Below is the exact copy-pasted content: ...

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