# All Questions

0answers
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### Selection of all the objects with the same style in a notebook

In a notebook, I would like to select all the cells with the "Text" style to change their style. How is possible to do this with a automatic process ? For the moment, I can to do it only cell by ...
0answers
38 views

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2answers
165 views

### How do I plot a space curve as a ribbon?

I know Mathematica has a built in Tube function, but I want to be able to change the parameters of a ribbon and visualize that. Is this possible? How do I do this? ...
0answers
4 views

### Button to close cells

I want to have a button that closes cells with a specific tag. The following code does what I want: ...
0answers
14 views

### using solve command

I used solve command to solve a set of nonlinear equations and got this error: Solve was unable to solve the system with inexact coefficients or the system obtained by direct rationalization of ...
3answers
297 views

### Solving an equation takes too long

I am trying to solve the following equation func[a, b, c, d, e] == 0 where ...
1answer
58 views

### Combine three 2D graphics with animation

I am trying to simulate three kind of points (different color) entering a 2D rectangular region from different sides with animation. Below is my code: ...
0answers
71 views

### Schrödinger equation for Hydrogen atom

I'm trying to solve Schrödinger 1D equation for hydrogen atom but I found several difficulties. To get in context I want to solve this equation For Z and l real and arbitraries. To start with I ...
1answer
2k views

### How was Mathematica built?

I've been wondering this for a while now: How was Mathematica built? Is it written in Haskell? C++? I'd love to get a taste of the wizardry behind this incredible software.
1answer
58 views

### LinearModelFit: How to compute R-squared? [on hold]

Is there a simple way to computed the R-Squared(adjusted and not adjusted), from the LinearModelFit? It has so many options, but none for the R-Squared, that I suspect there's a simple way to compute ...
2answers
65 views

### Expression of an integral

I am doing the following integral in Mathematica with $a>0$, $\iint e^{ -\left ( x_{1}+x_{2}-2b \right )^2/\left ( 4a \right )}dx_{1}dx_{2}$. My code is ...
7answers
533 views

### Brackets around each item in matrix

I have a matrix where every item in the matrix has its own brackets that I do not want. How can I remove the brackets around each item?
0answers
40 views

### Contour labels on SliceContourPlot3D?

SliceContourPlot3D doesn't seem to come with the option of putting contour labels on the plots as far as I can see. I'm using the ...
3answers
172 views

### sum involving binomial coefficient

To evaluate $\sum_{\substack{\text{even }k\\ 2\leq k\leq m-2}} \binom{m-2}{k-1}(k-1)$, where $m$ is an even integer. Running the following in Mathematica 10.3.0 (October 9, 2015) ...
1answer
86 views

### How to Minimize an NIntegral

My problem is to minimize in Mathematica a numerical integral. The command FindMinimum[With[{R=2.5},NIntegrate[(R*r1*a)*Sin[r1*a],{r1,1,R}]],a] does calculate ...
1answer
68 views

### Is it possible to recover the efficiency of ListConvolve when generalizing the convolution?

I've noticed that, while ListConvolve is very fast, it becomes much slower when you use anything but the standard Times,Plus as ...
1answer
37 views

### Issue with replacement rules screwing up a matrix

I am pretty new to using Mathematica as more than a calculator. Essentially my problem is that I am trying to calculate a quantity vector quantity $x=x_0 - A^{-1}F(x_0)$ where $x_0$ is a 3-entry ...
0answers
33 views

### Reaction-diffusion PDE with NDSolve: either very slow or very inaccurate

I am struggling to have Mathematica 10.3 solve a system of PDE's (with periodic boundary conditions and random initial conditions), but either it produces a set of very noisy InterpolatingFunction ...
0answers
46 views

### NMaximize is not doing what I intend [on hold]

Why does NMaximizegive the wrong answer in following script: ...
2answers
199 views

### upper envelope of data

Here is a ListPlot[] of some data. Clearly, there is a fairly smooth upper envelope - the question is whether there is an nice way of extracting it...
2answers
54 views

### Specify range and reverse for colordata in contourplot

The following two examples work ...
1answer
127 views

### Simple code to write differential equations in a matrix formulation

Is there a simple code to transform the following differential system equations : ...
3answers
223 views

### Reproduce image effect in Mathematica

How do I create the "dotifying" effect below in Mathematica? I have tried to use Rasterize first to get the image pixelated, but how do I get the disc/circle ...
0answers
21 views

### comments to a contributor of an answer [migrated]

How is it possible to alert a contributor of an answer of your post that you have answered to him ? In other words, to put his name in color in comments. I didn't find back the manipulation to this. ...
2answers
1k views

### NIntegrate error bound

I am trying to evaluate a highly oscillatory integral using NIntegrate. I fear that due to limited resources (time and/or memory), I will not be able to evaluate the integral to the desired precision. ...
0answers
7 views

### Linear vs. bilinear [migrated]

I'm tripping over something elementary: Suppose $f:\mathbb{R^2}\rightarrow X$ is linear, then $f(x+y)=f(x)+f(y)$ for all vectors $x$ and $y$. Now suppose that $f$ is also bilinear and in particular ...
1answer
52 views

### Plotting a function based on complicated integral

I have this function : f[Lambda_] := K Integrate[x Exp[- x^2-Lambda x] HypergeometricU[-Lambda,1/2,(x+ Lambda/2+2)^2],{x,0,Infinity}]; where ...
1answer
72 views

### UnitaryMatrixQ function not returning true for a unitary matrix

So I know this matrix is unitary. It's a well proven fact in quantum mechanics and you can even check for yourself on pen and paper, Heres a quick proof: Assume $H$ is hermitian (i.e. $H^\dagger=H$) ...
1answer
45 views

### Off[FinancialData::notent] fails on first run but works thereafter

Off[FinancialData::notent] fails on first run but works thereafter. So what good is it in this case? Is there a trick to force first time success? I've tried ...
0answers
146 views

### Why does Mathematica report that $\int_1^\infty\frac{\sin(\sqrt{x})}{\sqrt{x}}dx$ = $2\cos(1)$?

Mathematica 10 gives the following very odd result, Integrate[Sin[Sqrt[x]]/Sqrt[x], {x, 1, ∞}] (* 2 Cos[1] *) which seems unintuitive. The integrand has an easy ...
1answer
5k views

### What does “Tag Integer is Protected” message mean?

(Newbie question) For every function I define I get this message: When I close and reopen Mathematica, and re-enter the function definition, I don't get the message anymore. What does it mean?
1answer
51 views

### Densityplot: isolines

I'm plotting a densityplot map from interpolated data. I need to draw lines in which the value of my function is constant (isolines), but to be constant is not the function itself but a manipulation: ...
2answers
5k views

### Can Reduce *really* not solve for x here?

Sometimes I get the feeling I'm just flailing blindly with Mathematica. Is solving for $x$ in the equation $$\frac{\cosh (x/2)}{x} = \sqrt{2}$$ really beyond the scope of Mathematica? I try to ...
1answer
759 views

### Why is this 2D plot so slow?

I first do a 3D Plot of four surfaces (eigenvalues of a $4\times4$ matrix) over $kx,kz$ (setting $ky=0$ all along). And then I try to give a 2D plot along three connected particular lines in ...
2answers
4k views

### How do I work with Root objects?

I want to solve the trigonometric equation : $$(3-\cos 4x )\cdot (\sin x - \cos x ) = 2.$$ I tried Solve[(3 - Cos[4*x])*(Sin[x] - Cos[x]) == 2, x] It returns the ...
4answers
179 views

### ParametricPlot3D for only part of a sphere

I want to plot the region of a sphere that satisfies the equation $$\tan\theta\geq-\frac{z}{x\cos\phi + y\sin\phi}$$ where $x$, $y$, $z$ are my parameters. The spherical coordinates $\theta$ and ...
2answers
162 views

### How to draw a family of planes and its envelope?

Motivated by a question in MSE, I have the following question: How can I visualize the envelope of the family of planes $$2ax+2by-z+a^2+b^2=0, a,b\in\Bbb{R}$$ which is given by the ...
4answers
2k views

### Compiling more functions that don't call MainEvaluate

I would like to use Compile with functions defined outside Compile. For example if I have the two basic functions ...
0answers
43 views

### Definite integral evaluation

I want to evaluate the following integral: g[T_] := Integrate[(x^4*Exp[x])/((((A*(x^4) (T^4) a^4)) + (v/L) + (R*T*x)) (((Exp[x] - 1)^2))), {x, 0, (d/T)}] ...
2answers
813 views

### video image recognition [closed]

Has anybody experience with video and image recognition? I've made a video of two teams playing soccer. Now I would like to translate each soccer-player to a (x,y) coordinate and follow them during ...
12answers
5k views

### What are some useful, undocumented Mathematica functions?

There have already been some questions about some undocumented functionality in Mathematica. Such as (please add to these lists!) How can one find undocumented options or option values in ...
1answer
76 views

### Error propagation code

I have a code for error propagation :- ...
2answers
164 views

### How can I get the solutions of $x^n-x-t=0$ in hypergeometric form?

$x^3-x-t=0$ has three roots that can be expressed in hypergeometric form x_1=-1-\frac{t}{2}{_2F_1\left(\frac{1}{3},\frac{2}{3};\frac{3}{2};\frac{27t^2}{4} \right)}+\frac{3t^2}{8} ...
1answer
35 views

### Reading an exported List

I have exported a list of 2d coordinates as a List: Export["F:\\coordinates.dat", coordinates, "List"]; You can access the ...
0answers
75 views

### Differential equations with rational functions as solution

I have some families of nonlinear, first order differential equations. When I try to use DSolve, I usually get a mess (if anything at all) in terms of ...
2answers
188 views

### Does PrivateFontOptions -> {“OperatorSubstitution” ->False} fail in version 10?

Please consider the following, version 10.0.1, OS X Mavericks: ...
0answers
22 views

### Can JLink return a structured object?

What I want to achieve seems obvious but I cannot figure it out: I need to find a way that when I send an expression to be evaluated from a Java back end to a Mathematica kernel, I can live with it ...
2answers
188 views

### Plotting a function with three real arguments using transparency

I would like to plot a real function with three real arguments by assigning a transparency and color to the function values. The smallest value in the plotting range should be fully transparent, the ...
1answer
186 views

### Rendering a 3D volume with Image3D

I have 2D JPEG images, of 1024 x 1024 pixels, corresponding to a 500 x 500 square micron section. These images are taken from slices of tissue, each slice seperated by 10 microns. I've been trying to ...
2answers
64 views

### Small World network on a square grid

My aim is to generate a 2D Small World network on a square grid. i.e. 20x20. With a probability of 5%, one node rewires from an adjacent node to a random node of the grid, allowing some long distance ...

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