0
votes
0answers
53 views

Fourier-style solutions to differential equations, not piecewise polynomials

NDSolve returns piecewise polynomials. Is there any way I can get a single (non piecewise) function consisting of sines and cosines instead? Sort of a "Fourier approximation" to the solution of my ...
10
votes
2answers
202 views

Plot of $\sin(x^x)$ is missing from $x=143$

When plotting the graph of $\sin(x^x)$ I noticed that there is no plot from about $x=143$. I don't suppose there is a purely mathematical explanation for this? So, why is there no graph in ...
0
votes
0answers
75 views

Phase space of a system of differential equation

I have a system of three Coupled nonlinear equation of a physical system and i would like to plot the phase space. My system is a chaotic system dependant of three variable dependant of time (l1, ...
2
votes
1answer
67 views

Problems with QueueingNetworkProcess [closed]

I have a two stage queueing network and want to vary the number of servers at the second node. The input data and the Manipulate command is below: ...
1
vote
0answers
69 views

Possible memory leak in FindMinimum? (MMA v10.0)

So I was running some code when I noticed Mathematica was gulping memory, and after some debugging I think the culprit is found. It turned out the function ...
2
votes
2answers
153 views

Symbolic vs numerical integration

This is related to a question that I asked before but didn't resolve quite well. I want to obtain the solution of the following expression analytically: ...
0
votes
0answers
33 views

File filter in SystemDialogInput

I want to write a SystemDialogInput function that allows user to choose a file from a directory. In the directory, there are two kinds of image files: Atom images: The name of the file is in the ...
4
votes
2answers
85 views

MeshRefinementFunction missing points

I'm doing some FEM on a rectangular region with a spherical cavity: ...
1
vote
1answer
57 views

How to refer a number in a list with two columns, first one is a number and the second one is empty? [closed]

Let's say, I have defined a list as list = {{-31, -31}, {52, }, {34, -11}, {-38, }, {78, -44}, {-36,14}, {-9, 98}, {33, 6}, {82, 99}, {-85, -10}} As you can see, ...
12
votes
5answers
351 views

How to extract a contour line (or a region) from a ContourPlot?

Given a ContourPlot with a set of contours, say, this: is it possible to get the contours separating domains with the different colors in the form of lists? ...
1
vote
0answers
31 views

Changing from Cartesian to polar coordinates in partial differential equation [duplicate]

I have a partial differential equation: $$\left(x^2+y^2\right)\frac{{{\partial ^2}u(x,y)}}{{\partial {x^2}}} + x^2\frac{{{\partial ^2}u(x,y)}}{{\partial {y^2}}}=0$$ How to change from Cartesian to ...
7
votes
1answer
117 views

Add terms to nested list

Suppose I have a nested list of the following: list={{1,2},{5,8},{4,1}...} I would like to add a number to each first term of the list. The output would be ...
2
votes
1answer
89 views

Automatic text-wrapping in labels in `TimelinePlot`

Part-related to this question and part-related to this one, I would like to make use of the new features of TimelinePlot in 10.3, but would like to incorporate some ...
1
vote
1answer
27 views

Length in Compile encounter “type Integer encountered in assignment of Type Real ”

Compile[{}, Module[{n}, n = Length[{1, 2, 3, 4}]; n = n/2]] The above code will emit errors Compile::cset: Variable n of type _Integer encountered in ...
1
vote
1answer
56 views

ParallelTable should distribute dedicated evaluation range to different kernels

I have 4 kernels and would like that in ParallelTable: ...
-7
votes
2answers
61 views

How to solve for the eigenvalue in matrix? [closed]

For which value of $a$ in the matrix {{a,2}, {3,4}} has the matrix eigenvalue of $0$? How to solve it in Mathematica?
6
votes
4answers
196 views

How to generate two group of $n$ random numbers in $U(0,1)$ such that sum of these two groups equal? [closed]

I want to have two groups of $n$ random numbers $u_i$ and $v_i$ in $U(0,1)$, such that $\sum u_i = \sum v_i$ What I tried is: I can firstly get $u_i$ by ...
0
votes
1answer
24 views

Why can't I change the Magnification in Printout Style in Default.nb

This happens with Mathermatica 10.3.1.0: When working with a notebook, I can choose between different working environments. However, they inherit their settings from Default.nb situated at ...
-2
votes
0answers
45 views
1
vote
2answers
95 views
2
votes
2answers
68 views

intermediate steps of simplification of algebraic expression without evaluation [closed]

I am using MMA do do some algebra and I need to do some simplification. For example, I have the following expression $$ x^2 \left( \frac{6 \left(2 c_1 x^6+c_2\right)}{x^4} \right)-x \left( 4 c_1 ...
0
votes
1answer
45 views

How to represent one variable in terms of others in a system of equations? [closed]

I have an pretty complex equation set But when I clicked Ctrl+Enter (a.k.a Evaluate Cell), nothing happened. What should I do?
1
vote
0answers
29 views

How define shortcuts to specific OptionInspector points?

I often assign label to cells by OptionInspector (SHIFT + CRTL + O) > CellFrame > etc. It would be great to have the possibility to jump directly to CellFrameLabel or, even better, to edit the label ...
-1
votes
0answers
29 views

How to draw database diagram when connected to SQL Server via Mathematica [closed]

Is there a way to draw database diagram in mathematica?
2
votes
0answers
89 views

What is recommended way to define my function option

In Mathematica 5.x days many packages used the following standard mechanism to read option values ...
2
votes
0answers
35 views

Generation of Space Representation of non-crystallographic Point Groups

In Mathematica the command FiniteGroupData[{"CrystallographicPointGroup",<group number>}, "SpaceRepresentation"] yields the space representation ...
2
votes
2answers
56 views

Manually assigning Axes label position in Plot3D

How can I adjust the position of axes labels with respect to the axes they are bound? Like shifting slightly right or left. I do not what to destroy the graphics' dynamics and render it 2D. ...
4
votes
1answer
87 views

System of equations is solved by NDSolve over just a tiny domain

I'm solving numerically a system of differential equations with the use of NDSolve. The numerical integration works only a very small interval of the argument. I'm ...
-2
votes
0answers
53 views

NDeigensystem returns complex non-hermitian error for the calculation of vibrations of a cantilever [duplicate]

We are trying to use NDEigensystem to solve for the vibration of a cantilever with a triangular cross-section. The relevant PDE is $\mu \nabla^2 \vec u + (\lambda + \mu) \nabla(\nabla \cdot \vec u) = ...
3
votes
1answer
52 views

Havin the problem with solving a nonlinear overdetermined system of equations

I am having a problem to solve a nonlinear overdetermined system of equations. According to one of the previous posts, I tried NMinimize, but it didn’t work. Shall ...
1
vote
1answer
32 views

Issue plotting PDE solution with manipulate

I am trying to plot the solution to the following PDE with the help of mathematica, however, when trying to employ manipulate to animate the behavior, I find that if I try this: ...
1
vote
1answer
55 views

How do I write a function inside a ArgMin

I want to solve this ArgMin[NIntegrate[(Tanh[x] - Erf[x/a])^2, {x, -5, 5}], a] and it does not work, what is the correct way to do this? ...
4
votes
2answers
143 views

Insufficient size of Graphics

The following code returns a framed text box that is longer than the standard width of `Graphics'. ...
3
votes
2answers
55 views

Problem with FindFit: Low quality of estimated parameters

I'm trying to fit a Cole-Davidson formula: ...
-5
votes
1answer
52 views

Finding a seven-digit number with all of its prime factors less than 20? [closed]

How can I find a seven-digit number with all of its prime factors less than 20? I have no clue how to do this.
0
votes
0answers
14 views

Export a .NOFF file without color information

I have the following piece of code: ...
0
votes
0answers
55 views

Implicit differentiation dx/dt?

I am trying to find $\frac{\partial t}{ \partial y}$ as a function of $x$, $y$ and $\frac{\partial t}{\partial x}$ if both $x$ and $y$ depend on $t$ for the function ...
2
votes
1answer
50 views

Plotting certain time points in a parametric equation? [closed]

I'm using Mathematica 5.0 and I have the following problem. I have the following parametric equation that I plotted successfully. ...
1
vote
2answers
72 views

What's the easiest way to remove overall factors from polynomials?

I have code that outputs polynomials (in #1) such as the ones below (note that the trailing Function character ...
4
votes
0answers
50 views

Numerical instabilities of a convection-(non-)diffusion equation when shrinking from a square to a triangular domain

I am trying to evaluate a parameter-dependent indefinite integral using a PDE-based scheme I described here, and I'm having some trouble when I try and cut down the domain from a square to a triangle. ...
-5
votes
0answers
27 views

what's my air speed if i know these details [closed]

What is the minimum air speed required of an F4 phantom aircraft to accelerate at 10g while pulling the nose up from a 20 degree pitch down attitude?
3
votes
1answer
68 views

How can I numerically pre-compute an indefinite integral with a parameter?

Suppose I have a function $f(t)$, and I want to compute its indefinite integral $$F(t)=\int_0^tf(\tau)\mathrm d\tau.$$ Moreover, suppose that, for any of a number of reasons, I require this integral ...
0
votes
1answer
74 views

How to solve this recursive system?

I try to solve the equation system as ...
2
votes
1answer
60 views

Notebook Magnification changes - Why?

I have written a notebook but in order to edit it, I prefer 125% magification or even 150%. I know Window>Magnification. Also there is a small symbol on the right bottom of the notebook, where I can ...
0
votes
1answer
44 views

Need Help with solve function [closed]

I'm trying to re-write this function x = e^(-(r+(1/2)*sigma^2)*t-(g)(sigma)*sqrt(t)), as an expression of "g" instead of "x" ...
2
votes
2answers
233 views

Follow each pixel brightness in set of images (Memory constrained)

I have a set of 2700 consecutive png images (8bit, 2048*2048 pixels). I would like to visualize the intensity variation of each pixel vs. image number. Here is an example of 10 images: ...
3
votes
0answers
40 views

Possible Bug with DateObject

So my questions is going to be hard to duplicate because I am not sure when or why it happens. I've read here several bugs with DateObject, but none of them ...
4
votes
0answers
66 views

3D orbits of moons around their respective planets

I have seen a lot of solar system models (both animated and not), but I am trying to replicate the same thing with moons. Either just one planet and its lunar system or the our whole solar system with ...
0
votes
0answers
34 views

How to run code in two notebooks simultaneously [duplicate]

I have the problem that I cannot run code in a second notebook when another notebook is being executed (here only a single core is used). The CPU of my computer has 4 cores (Win 10, Mathematica ...

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