# All Questions

81 views

### Failure in the use of FullSimplify

My question is about an apparent failure of the function "FullSimplify" to simplify an easy algebraic expression. This is the expression that I ask Mathematica to evaluate: ...
355 views

### Plotting random circles in a square

How can we draw 20 circles which have random radius in a specified range, with random positions. All centers must be in a square with side=10 (for example centimeter): every overlapping between any ...
122 views

### How to create a smile animation in Mathematica?

I want to create a yellow smile, with normal mouth which smiles in cycle. I only know that I need to use CDF player and Manipulate, but do not have any idea how to do that. Thanks!
284 views

### How to compile this function

I want to compile my function that calculates the energy of a particle system. This is what I've tried: ...
44 views

### Defining a function in terms of a solution returned by Solve

The title is a little ambiguous, but I didn't know how else to put it. What I'm trying to do is solve a system of equations ...
126 views

### Superimposing ListLineIntegralConvolutionPlot with transparent noise over ListContourPlot

I have an array of 128x256 data points in a rectilinear array. For each point there is a 2D vector quantity and a scalar quantity (normalised to -1 <= x <= 1). I very much like the ...
114 views

### How to write a pattern that matches all functions

What is the correct way to match a function in an expression in the way that Cases[Sin[x] Cos[x], _Sin | _Cos, {0, Infinity}] matches ...
460 views

### How to improve performance of BesselJ to the level of GSL?

Consider the following code: zs = N /@ Range[0, 12, 10^-5]; AbsoluteTiming[bessels = BesselJ[1, #] & /@ zs;] Length @ zs I've tried to measure only ...
84 views

### Orderless storage of tabulated function values

I would like to elaborate on my previous question Function of arguments given in non-fixed order and a relevant related one Best practice of passing a large number of parameters to functions I find ...
250 views

### Strange Boundary NDSolve Problem

Mma10.1 doesn't work with the following boundary problem: ...
80 views

### What is a good way to check what kind of a function a function is?

i want a module or function or switch or If (whatever works), what asks if a function is an e function or a polynomial(a hole number one or fractorial), a exponential function, a logarithm function ...
173 views

### How to fill the closed region by ParametricPlot with solid color?

I am interested in the following implicit curve with parametric equation: $$\left\{\quad \begin{array}{rl} x=& 9 \sin 2 t+5 \sin 3 t \\ y=& 9 \cos 2 t-5 \cos 3 t \\ \end{array} \right.$$ ...
73 views

### Ordering in noncommutative multiply

I have an expression like s ** p1 ** p1 ** p2 - s ** p1 ** p2 ** p1 Which should be zero because the commutator between p1 ...
487 views

### Using Greek $\LaTeX$ fonts

I want to use the $\LaTeX$ font in graphics. For text/numbers, this is easily done by FontFamily -> "CMU Serif" (on Ubuntu) like this: ...
92 views

### Use FindRoot to get the root with minimum imaginary part

For example, define test[z_] := Cosh[0.5132928614530164 z] + 0.5934823341977118 Sinh[0.5132928614530164 z] And ...
139 views

### Actual bins used for Pearson Chi Square Test

PearsonChiSquareTest[data, dist] computes bins for data as a step towards calculating the test statistic. For continuous ...
297 views

I hope this is not a silly question, since there are plenty of questions on Thread and MapThread. However, I still cannot quite ...
144 views

### BarChart3D: varying individual bar color

I've been working with a chart like so: ...
171 views

### Computing Reversible CA with CellularAutomaton

This computes and plots 127 steps of the evolution of 150R (the reversible version of rule 150). ...
99 views

### Problem with writting into a matrix in Mathematica [closed]

I have declared a matrix using S = ConstantArray[0, {246,246}] And when I try to write into it by a loop I get the following error "Tag Times in 0\ Null is ...
72 views

### Mathematica SQL command that counts records in table

Is there a DatabaseLink command other than SQLExecute that can be used to count the total records in a database table?
694 views

### How to draw a dodecahedron with each face modified to a pentagram?

I'd like to draw a dodecahedron with each face carved on the sides so it becomes a pentagram. I wonder how to start to do this kind of task in the Wolfram Language? Edit: The result should still be ...
220 views

### Precision while calculating Fourier transform

I'm trying to understand how precision works in Mathematica. Particularly I'm calculating discrete Fourier transform using the Fourier function and calculating it "...
379 views

### How to programmatically ask if Mathematica is running as an Administrator

To avoid execution problems in a program I need to know if Mathematica has been "Run as administrator". What would be the cleanest way to programmatically getting this information?
102 views

### when two associations are equal?

<|a -> 2, b -> 3|> == <|b -> 3, a -> 2|> returns False; can anybody explain why? If I am not mistaken ...
51 views

### Unexpected behaviors with Edge Weights

Noticed some bizarre behavior when subgraphing on weighted graphs, which probably extends to graphs with arbitrary edge properties. I construct a weighted graph with five edges, defining a specific ...
153 views

### How to plot points using ParametricPlot3D?

I have the following Mathematica code: ParametricPlot3D[{{0 + 0*t, 10 - 1*t, 9 - 1*t}, {7 - t, 7 - t, 6 - t}, {0, 0, -1}}, {t, 12, -20}] The last "parametric ...
305 views

### Plot a function on a restricted domain

I want to plot a function $f:\mathbb R^n \rightarrow \mathbb R$ restricted to a domain $D \subset \mathbb R^n$. The domain $D$ is usually specified as the set of zeros for a set of polynomial ...
56 views

### Multiplying two parametric solutions

I'm solving two (1-parameter) differential equations and I want to plot the product of their solutions, how do I do this? Here's the code, ...
48 views

### Issue with Table [closed]

I have a quick question about using the table command in mathematica. Suppose that I define ...
67 views

### List manipulation performance or how to make independent list copy

I have a task to solve some system of equations with NSolve and print graph of it, depends on parameters. Something like this (maybe it is not a good example and does not always have a solution, but ...
121 views

### Formatting the results from solving a differential equation

{{x[t] -> 600 (t + I π t - 50 Log[50] + t Log[50] + 50 Log[50 - t] - t Log[-50 + t])}} After solving a differential equation, I get an answer in a form where I ...
37 views

### Orthographic view (top,bottom,left,right,rear,front) and Isometric view using ViewMatrix [duplicate]

I want to know how to obtain the orthographic view (top,bottom,left,right,rear,front) and Isometric view using ViewMatrix. I read the ViewMatrix documentantion but couldn't figure out how to do it.
114 views

### How to apply ReplaceAll to denominator?

Here is the simple task. In reality, it's far more complicated, but it comes down to this. I want to take the expression $\frac{y}{x^2}$ and replace $x^2$ with $k$. This doesn't work: ...
96 views

### plotting sine of a wiener process and calculating derivative

How can I plot the sine of a Wiener process and compute its derivative? I only found the WienerProcess function in mathematica (version 9), but I'm not sure how to apply it.
876 views

### Integrate gives wrong results

Integrate[a/(Sin[t]^2 + a^2), {t, 0, 2 Pi}] $$\int_0^{2 \pi } \frac{a}{a^2+\sin ^2(t)} \, dt$$ gives $0$ This cannot be true. What is going on? If I insert a ...
64 views

### Problems with indexes in a Do-cycle and CoefficientArrays

I have a system of linear equations with variables $A_n$ and need its coefficients in a matrix form (Transform linear system into a matrix form). I'm trying to do that through a ...
229 views

### ContourPlot has weird Jagged line

I'm trying to make a series of contour plots, but pretty much everything I try (and I've tried many different equations) ends up with at least one jagged line of the form seen in the image. I don't ...
116 views

### how to partition the matrix into blocks of different dimensions

i have a matrix ...
243 views

### Bifurcation diagram for iterative map [duplicate]

I have a mapping function (cubic logistic map) f(x)=rx(1-x^2) and I need to make multiple bifurcation diagrams, showing stable equilibria and periodic orbits for 400 equally spaced r values ...
566 views

### How to solve the differential equation with Duhamel's integral?

How do I solve a differential equation with Duhamel's integral? I tried to solve it with NDSolve, but failed: ...
105 views

108 views

### How to find the domain of an arbitrary function?

I got stuck here: fuu[x]:= 1/x +2x^2 Reduce[Exists[{x},fuu[x]],Reals] of course it doesn't work like this. How can i check if there will be divided by zero or if ...