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2
votes
1answer
32 views

A ListPlot with multiple lines, fill to the axis, no thickness of the lines, and all fill in the same color

I have created the ListPlot shown below (from data in a multidimensional list), but it is not exactly what I aimed for. I aimed for everything shown, except I do not want any lines to border the ...
-1
votes
0answers
20 views

Troubleshooting backward/forward mode of differentiation

When I try to generate my finite element, the following warning/error appears when I want to define the tangent matrix, using the standard comand K=SMSD[R,a,j]: <...
4
votes
1answer
86 views

How to set up a Fourier transform?

I am having trouble figuring out how to set up the Fourier transform to: ...
0
votes
1answer
27 views

How to plot the Imaginary values of a function

When i use the following code in Mathematica9 to plot the imaginary values of the function all the values are plotted on the Y axis. It is seen that the X values are taken as zero. ...
0
votes
1answer
112 views

Finding recurrence formulas from procedural code and output lists associated with integer sequences

This code outputs 37 sequences and takes about 15-minutes to run. I would like to be able to see how many and which variables { i, j, k, m, n } each of the 37 ...
1
vote
1answer
35 views

Maximize violate constraint of non approximated function

here is my code Maximize[{-(10/17) - x + (20 (1 + x))/(17 (2 + x)), 0 <= x <= 1.5}, x] The result I got: {6.66134*10^-16, {x -> -9.79755*10^-16}} As you ...
1
vote
1answer
33 views

Assuming x real, simplifying or refining Im[1/(x+i)] doesn't yield anything

I think it is straightforward from the title, Simplify[Im[1/(x+I)], x > 0] spits out, Im[1/(x+I)] while I would have ...
0
votes
1answer
32 views

Highpass/lowpass a set of {N,2} data, where first column is the time?

How can I highpass/lowpass a set of data, where the sample rate is not fixed, but is the first column of data, ie when data = {{t1,x1},{t2,x2},...{tN,xN}}?
2
votes
1answer
41 views

How to remove curly brackets in a two dimensional array near the edges?

Suppose I have a matrix {{1,2,3},{4,5,6}}. I want to remove the curly brackets near the edges, i.e., I want an output as '{1,2,3},{4,5,6}'. Somebody please help me to solve it.
8
votes
1answer
277 views

Optimization of the following code

Consider the function $$ h:[-1,1]\times I_{\sigma}\to I_{\sigma} $$ $$ (\omega, x)\mapsto \sqrt[3]{x + \sigma \omega} $$ where $ \sigma > \frac{2}{3\sqrt{3}}, I_{\sigma} = [x_-(\sigma), x_+(\sigma)]...
0
votes
0answers
55 views

Mathematica does not evaluate large expression

I want to apply Conjugate[] to a certain quite long rational function of some parameters. My problem is that although it evaluates perfectly fine on each single part of the expression, Mathematica ...
12
votes
1answer
588 views

What is the use of FullForm in Mathematica?

I would like to know where this "FullForm" in Mathematica will be useful. Kindly provide some examples. I just started learning Mathematica. If my question is wrong or not correct. I'm sorry about ...
1
vote
1answer
70 views

Variable substitution like usual maths

So... I'm trying to get some simplifications on equations using own defined variables, but the tries I gave didn't result on what I wanted. The problem: I have 2 variables defined as: ...
-1
votes
0answers
33 views

Exporing as CSV file with a header and custom field separator

I want to output a table in a csv-file using the Export function, how can I specify the field separator or the comma character and how can I define a header line for the output?
1
vote
1answer
24 views

Iterate through union of lists to correspond to each element a list of names of the lists to which the element belongs

Say I have several lists L1, L2,L3 an I want to correspond to each of the elements of Union[L1,L2,L3] a list of list names to ...
0
votes
1answer
53 views

goodness of fit test for grouped data

I have the following grouped data: Can someone please tell me how to run a goodness of fit test to test if this data is from a normal distribution? I would like to do this without estimating the ...
5
votes
3answers
217 views

Problems with solving PDEs

I am using NDSolve to solve the two equations: ...
0
votes
1answer
71 views

DSolve returns unevaluated(I need a closed or numerical solution for this system and plot solution)

I am trying to find a solution to this system of differential equations but the program gives the same output without any messages. I would like help. Please find the Mathematica code posted here. a ...
0
votes
1answer
40 views

Joining a list of lists together when generated from a table

I'm batch importing some summary files for analysis ...
3
votes
0answers
52 views

Large Dynamic expressions and responsive UI's

I have a ListLinePlot with 40,000 points. When it's displayed on-screen the input fields are not responsive (text appears slowly well after the user is done typing)....
1
vote
0answers
24 views

How to plot a graph with fixed Frame width and height while keep PlotRange Automatic?

I'm trying to plot a graph and set Frame width and height by given numbers. However, I found I could only fix the Frame height, the Frame width varys with data plotted. For example, compare ...
3
votes
2answers
155 views

How do I restrict an interpolated function to only take values > 0?

I have a list of points which looks like this when plotted with Joined -> True: I'm interested in the area under the curve with x-axis > 0 as a ratio to the ...
0
votes
1answer
31 views

Selecting solutions that evaluate to positive

How to extract symbolic outputs of Solve that evaluate to positive at given values of parameters? For example, if ...
2
votes
2answers
137 views

Simplify appears to give different results

I have an issue with Simplify (and FullSimplify) giving a different numerical expression to the pre-Simplified expression. The function is an alternating sum of trigonometric quantities: ...
0
votes
1answer
26 views

Get Conditions for Variable to be Real

I have a complex definition of a few variables (that I got using s = Solve[1 - a x^2 - x^3 == 0, x]) and I now want to know under what conditions of "a" will each ...
0
votes
1answer
44 views

Generating a Large (possibly infinite list) of Formulas From A Group

Here's a little background, I have a finite list of linear formulas in 6 variables and 6 linear transformations in these variables. Obviously I can apply these transformations with /. to my current ...
-1
votes
0answers
42 views

How to Solve this partial differential equation [closed]

How to solve this problem by using Finite Difference Method. u is a function of "t" and "x", where alpha, B1, B2, Wr and R are parameters and phi = 0.1 (https://i.stack.imgur.com/bkqlW.jpg)
0
votes
1answer
52 views
3
votes
1answer
2k views

How to do continuous Fourier transform?

I want to do a Fourier transform to the below function by Mathematica. How can I do it? Here $c$, $d$, $a$, $L$ are constants. $$ w(r)= \left\{ \begin{array}{ll} -\frac{c}{\epsilon r} & ...
0
votes
0answers
84 views

How I can solve a Reynolds equation? [closed]

I want to solve the equation shown below. I don't know much about Mathematica. Can somebody help me? \begin{array}{l} \frac{1}{{{R^2}}}\frac{\partial }{{\partial \theta }}\left( {{P_0}\frac{{\partial ...
2
votes
1answer
137 views

Double Numerical Integral - precision is not improving answer

Consider this two-dimensional integral ...
3
votes
1answer
130 views

Analytical form of 2d integrals relevant to graphene

This question is continuation of my previous post. Alex Trounev was very helpful in fixing a crucial typo in the analytic solution known from the article "Density Dependent Exchange Contribution to ∂𝜇...
3
votes
3answers
340 views

Nearly equally spaced 3D-mesh

How to mesh a volume (3D region) with nearly equaly spaced vertices? Example: Disk with radius 50 and height 15 ...
2
votes
1answer
50 views

How to differentiate a function that is a function of other functions?

I am trying to differentiate the function epsilon1 with respect to u, but why this does not give me any output? ...
4
votes
1answer
61 views

Blurry labels in GeoGraphics

I want to keep the same GeoZoomLevel, but increase the resolution of the labels. I'm struggling to control that: ...
0
votes
1answer
49 views

How to define a cross product of two orthogonal vectors?

t[s], n[s] and b[s] are three orthogonal vectors. I define a cross product ...
1
vote
2answers
72 views

fitting a monotonic function?

Let's say I have a few points and derivatives given for a function and I'd like to find the best fit through the data, which is monotonic. For example, if I take a polynomial ansatz, I get ...
0
votes
1answer
37 views

Changing the value of a variable based on output of manipulate

I'm trying to use the output value of a manipulate to define a variable that will be used for a calculation. I've created a minimal example of what I'm trying to do. In this case, I'd like to use ...
0
votes
0answers
60 views

Removing duplicate lists from a list of lists [closed]

I have a list of lists, with some of the lists being duplicates. I would like to remove the duplicates to have a list of unique lists, but am not sure how to do it! Also I have a list of lists of ...
0
votes
0answers
57 views

Is there a beginners tutorial for Wolfram Engine users?

I was taking a look at WolframEngine. The fact that it is freely available, virtually making Wolfram tools and language accessible to anybody is very much attractive! Nevertheless, the first impact ...
2
votes
0answers
69 views

Lambda calculus reduction in Mathematica

Are there any built-in functions for reducing lambda terms in Mathematica? If not, how might one do it? I've heard of Function, which is good for $\beta$-reduction, ...
5
votes
0answers
104 views

Status of Streaming package

I see the Streaming package mentioned in this question How to use Streaming package in v11.1? with advice on getting it working in V11.1. I've failed to get either the built-in version or the patch ...
2
votes
0answers
32 views

Mathematica: Remove argument from object with flat attribute

I have an object in mathematica with the attributes Flat and OneIdentity. I also defined the following substitutions: ...
4
votes
1answer
78 views

Colorize specific region in plane

The plane is divided into a grid and points is distributed on it. ...
2
votes
1answer
57 views

Replacement patterns

I wanted to ask if there was a way to quickly replace multiples of the same thing, instead of writing it so many times, for example: ...
2
votes
3answers
91 views

prime number digits less than n? [closed]

How can I ask mathematica to sieve with only primes with three-digit less than a given number. Thank you for instance I want to find the prime factor of 1337. Thank you
0
votes
0answers
59 views

Next maximum plot with results from NDSolve

I want to produce a Next-maximum-plot, i.e., I want to plot all local maxima $m_{i+1}$ against the local maximum $m_i$ in order to check for chaotic behavior. In particular, I have the following code:...
0
votes
0answers
45 views

Problem with importing data and interpolating it [on hold]

Here is the code data = Import["D:\\Third Semester\\q1.patxt", "Table"] And here is the imported data file with properly arranged data
8
votes
2answers
506 views

Contour plot of a sequence of spheres with increasing radius

I am trying to do a simple thing really, plot a sequence of spheres with increasing radii and I used a Do-loop to do it, but nothing happens, Please suggest what I can do to get the result I want? <...
1
vote
3answers
83 views

Summing all the times of a column

It is possible to add a last row in the table where I can show the sum of values of the last column. I would like to get the total time value... ...

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