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0answers
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Fourier series - value at a point

I would like to receive the value of the series in point (3,3). Plot3D[((27000000000*((0.2)^3))/(12*(1-((0.2)^2))))Sum[Sum[((((0.2(mPi/6)^2)+((nPi/4)^2))*(( ...
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0answers
6 views

NDSolve and equations of motion

I am trying to use NDsolve to solve a set of coupled second order ODEs. Here are the initial conditions: ...
0
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0answers
9 views

how to get from this expression to the next

I want to get to this expression (4FL^3)/Eb^4 however, no matter how I try to rearrange the given expression I am struggling to figure out how to get to this expression below? (FL^3)/(3E(b(^4)/12))
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1answer
20 views

Special Case of Filling Between Curves

Hi guys, Thank you very much in advance! Best regards Nina
0
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0answers
23 views

List of Coordinates at Mouse Position

I have the following image I want to semi-automate the process of me collecting coordinates for all the vertices. What I have in mind is putting my cursor over each node and appending the coordinate ...
1
vote
0answers
30 views

Is there a way to get the exact measurements on the screen in mathematica?

Suppose I want to make a rectangle that is 50mm x 70mm and I want to inscribe a ellipse with x radius 10mm and y radius 15.5mm centered at 20mm from top and in the middle across. I can get the ...
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0answers
21 views

TensorProduct not working

I am currently trying to get the following to work: ...
-1
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0answers
27 views

One dimensional wave equation [on hold]

The sermon about the one dimensional wave equation is, that all solutions have the following form (to simplify we include the velocity into time t'= c t): $$ u_{t t} - u_{x x} = 0 $$ $$u(x,t)= F(x+...
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0answers
26 views

Mapping onto torus

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2
votes
1answer
33 views

TensorContract and TensorProduct problem

I am trying the calculate the Kretschmann scalar $K$ of a metric $$K=R^{abcd}R_{abcd}$$ where $R$ is the Riemann tensor. If I do ...
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0answers
4 views

How to evaulate salesmen objectively? [migrated]

Each salesman will sell product to three kinds of person,each kind of customers has a different response rate,I will mark these customers level A,level B and level C. According data here,how to ...
9
votes
4answers
600 views

Is there way to randomly distribute points within a circle on the surface of a sphere?

I'm attempting to set up a situation where on a 3D sphere, I choose a random point and construct a circle around this point with some radius. I then want to randomly distribute points within this ...
5
votes
2answers
103 views

Convert Histogram from frequency of string length to percentage

I have the histogram: dataPnJ = StringLength[StringSplit[ExampleData[{"Text", "PrideAndPrejudice"}]]]; Histogram[dataPnJ] I am trying to make the histogram show ...
2
votes
2answers
106 views

Represent list of lists as formatted grid

I have tried to figure out how to make these changes, but it mostly just ends up with me making it ten times worse. ...
2
votes
1answer
90 views

Testing the accuracy of numerically computed derivatives - alternative method

So I have asked this question earlier today: Testing the accuracy of numerically computed derivatives, This method works well for DifferenceOrder methods but upon reading https://reference.wolfram....
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1answer
34 views

How can I take the divergence of a symbolic vector?

I would like to compute expressions that have the following form: $$\left(\partial_{p_1} - \partial_{p_2}\right)^2 \left(\partial_{p_1} - \partial_{p_2}\right)^2 \frac{(p_1-p_2)\cdot(p_3-p_4)}{p_1^...
0
votes
1answer
46 views

How do I plot a parametric function? [on hold]

I want to plot this parametric function: $\qquad x=2\,\cos(\sqrt{12}t- π/3),\,y=4/\sqrt3 \sin(\sqrt{12}t- π/3)$ where $t$ goes from 0 to 8 I tried to make a plot, but I didn't know how because it's ...
2
votes
1answer
49 views

How can an envelope be drawn around a scatter plot?

Can Mathematica be used to create a ListPlot with the feature shown below; a line around the cloud of points? I am not entirely sure what rule would create the desired effect (i.e., what points ...
1
vote
1answer
40 views

NIntegrate over regions, FiniteElement options

I am using NIntegrate to integrate a 3-dimensional region. When I don't set any integration options, I get a warning The global error of the strategy GlobalAdaptive has increased more than 2000 ...
3
votes
1answer
33 views

Changing ContourStyle based on an inequality

I would like to create a bifurcation diagram with ContourPlot. Suppose I want to plot the contour 1-2*a*Q+3*Q^3==0 with ...
7
votes
1answer
331 views

Speed up animation

For a project I need to make a little animation showing what happens when you put two hexagonal lattices on top of each other and rotate one of them(Moiré pattern), and my advisor sugested using ...
0
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0answers
51 views

How to use deep clones in Mathematica

Is there a way to use deep clones in Mathematica? Maybe by making lots of different kernels. In order to execute multiple notebooks I need more than one kernel, is there a way to make them using C# ...
1
vote
0answers
31 views

Is it possible to plot a manifold from it's metric / line element in Mathematica?

i'm very new to using Mathematica and mostly just trying to work out what it can or can't do. I'm doing a course on differential geometry and was wondering if there might be a better way for me to ...
5
votes
2answers
76 views

How can dates be formatted with Tooltip in a DateListPlot?

After creating an association of time series as follows: ...
6
votes
1answer
73 views

Graph that visualizes subset relations

First, off I am a bloody beginner when it comes to programming in general and Mathematica in particular. I only started using it so I can make sense of my suggestions for the semantics in my syntax ...
0
votes
1answer
82 views

How can I simplify my geometric calculation?

Here is a math problem I am dealing with right now: Given ellipse $C$: $x^2/a^2 + y^2/b^2=1$ ($a>b>0$). Ellipse $C$ passes through the point $P$: $(1,3/2)$, and has eccentricity $e=1/2$. ...
1
vote
2answers
57 views

Testing the accuracy of numerically computed derivatives

I am calculating approximate derivatives by using NDSolve`FiniteDifferenceDerivative, so this works: ...
1
vote
0answers
25 views

How to get the NDSolve to seek only a real solution?

I use NDSolve to solve system of 2 ODE of 1st order: ...
0
votes
1answer
71 views

SmoothHistrogram plot is not smooth [on hold]

I used the following code to show a small hump near 5000. With R it's fine but for some reason Mathematica draws strange vertical lines. I tried several combinations of ranges. (Data from here or here....
1
vote
1answer
35 views

Identify and Assign Values to Regions in the Map

so I want to do a simulation of the spread of a certain disease in California with spatial considerations. As such, in order to carry out the PDE calculation, I will need to extract the region of ...
0
votes
0answers
33 views

Having trouble making a computation into a loop

I have written the following code which works properly. However, I need to run a part of it as a loop, but when I try to add a loop, I encounter many errors. I tried by ...
0
votes
0answers
35 views

How can I derive a scatter plot from histogram data? [on hold]

This is the code that generates the histogram. ...
0
votes
0answers
18 views

help needed to understand the syntax of the scatter plot graph [on hold]

how would the code/syntax for a graph like this, i need to replicate it with the information given
4
votes
2answers
242 views

Showing a point on a plot as a circle rather than a disk

Consider the following code: ...
0
votes
0answers
49 views

Solving time dependent boundary conditions heat PDE

I am attempting to solve the heat equation $\frac{\partial T}{\partial t}=\nabla^2T$, where $T=T(x,y,z,t)$, subject to the following boundary conditions: $\frac{\partial T}{\partial x}|_{x=10}=\frac{\...
0
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0answers
36 views

Could you help me convert my PDE into a boundary value problem?

This is my code. It works as an initial value problem, but I want to solve it as a boundary value problem. ...
1
vote
2answers
38 views

Plot multiple solutions for different t terms

I want to integrate a a simple function for different t values. At the moment I have the following code; ...
1
vote
1answer
56 views

Convert ProofNotes to $ \mathrm\LaTeX $ logic expression

The following code will generate some ProofNotes: ...
2
votes
2answers
87 views
1
vote
0answers
26 views

How to compute the multiplicative order of an element in a finite field

I want to find the multiplicative order of say the element {0,1,0} in GF[8]. I made a list: b = Map[GF[8][#] &, Tuples[{0, 1}, 3]] I tried: NestWhileList[b[[3]]*# &, b[[3]], # != b[[5]] &...
1
vote
1answer
42 views

How to Make Table Headings [duplicate]

In the code below, how can I add (left to right) column headings "n", "pp","aa"? There is also a shift in the alignment across the generated rows. ...
0
votes
1answer
44 views

How to make a function linear

I have a linear function, say f, and an expression like f[3x^2 - 8 a y^2 + 4 z b] where I know that ...
0
votes
1answer
65 views

Obtaining a parameter using Brent's method

Using Brent' method, I want to find a $g$ which minimizes $\Delta$ that is defined as $$\Delta=\sum_{n=1}^N F^2_n \tag{1}$$ where $F_n$ is $$ n(n-1)\mu_{n-1}+2Z\mu+2E\mu_{n+1}-2\alpha\mu_{n+2}-2\beta\...
0
votes
1answer
39 views

NDSolve::deqn: Equation or list of equations expected instead of eqns in the first argument eqns

I am new to Mathematica, actually, I am working on a project based on Swarm Intelligence. I am trying to run a simulation of sphere formation of 10 robots, but there is a problem in equations. Here is ...
2
votes
1answer
47 views

Does Mathematica assume that the order of numerical integration can be changed?

This question gives a 3-dimensional infinite integral where the correct result (I believe) depends on the order in which the variables are specified. Specifically ...
0
votes
2answers
58 views

Why can't I plot this surface?

I can't plot (x^z)-(y^z)=x*y. I've tried it with Geogebra and with Plot3D[x^z - y^z == x*y, {x, -1, 1}, {y, -1, 1}] in Mathematica, but in both images only ...
6
votes
4answers
288 views

Integration of three dimensional function gives wrong answer!

I have the following integration $$\int_{-\infty}^{\infty}d^{3}\mathbf{p}\nabla\cdot\frac{\mathbf{p}}{(p_{x}^{2}+p_{y}^{2}+p_{z}^{2}+m^{2})^{3/2}}$$ $$=\int_{-\infty}^{\infty}d^{3}\mathbf{p}\left(\...
1
vote
0answers
31 views

Weird display usage bug by Mathematica 12 on Windows 8 - how to fix it?

Since I've upgraded to Mathematica 12 on Windows 8, this very weird behaviour has started occuring: (Essentially: the notebook area gets shrunk and minified and an unusable black area appears.) It ...
0
votes
1answer
29 views

Reading and re-assigning variable

I am trying to create a table by iteratively calculating its values using a temporary variable accu: ...

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