# All Questions

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2answers
38 views

### help with plotting functions in Block and ContourPlot3D

I have a question regarding Block. In Doc, Block[{x=x0,…},expr] suppose we have two functions in ...
3answers
545 views

### Merging 4 matrices to one matrix

I am struggling with the task to merge four matrices as presented below. Since the matrices A-D contain more than just four entries it would be too complex to do it by hand. Is there a simple or ...
1answer
32 views

### How to make Button print the last updated point?

I am trying to create a graphics that outputs the population of a city on the graphics that is clicked. The problem is that it is not updating the last point that is clicked. Please help. ...
0answers
30 views

### Using Show to combine two plots made with DiscretePlot3D [closed]

I used DiscretePlot3D to plot my equation, but when I tried to combine two different plots into one, Show did not work. Do you ...
2answers
107 views

### Destructuring a list containing two items to use it as arguments to a binary function

I'm experimenting with the Through function. I suspect there is a way to use that function to obtain both the mean and difference of two values. But this doesn't ...
2answers
72 views

### Replace elements of a list if the conditional is false

There is a list: {1, {a, b, c}, 1, {1, 2, 3, 4, 5, 6, 7, 8}, {A, B, D, Z}} It contains sublists of different elements and several $1$s. The goal is to replace ...
3answers
205 views

### Making one list from two lists by grouping them in a special way

I have two lists: list1 = {{{x1,x2},{x3,x4}}, {{x5,x6},{x7,x8}}}; list2 = {{{x9,x10},{x11,x12}}, {{x13,x14},{x15,x16}}} I need to join them to get one list: <...
0answers
58 views

### Why is Log[8 E^(3 Log[0.5]) != 0 [closed]

My wife and I have tried to calculate Log[8 E^(3 Log[0.5]) on a TI-Nspire and we got the result -8E-14. We have changed th settings of calculation to Exact and the result was 0 (correct) If I use ...
1answer
29 views

### Converting String in “Data” Format within Mathematica [closed]

Hi I have a simple question. Given a random string in the format accepted by the Import[fileWithString, "Data"] i.e the file contents being ...
0answers
25 views

### Lightweight Grid: transfer a file to the master kernel?

I am trying to run code on a Lightweight Grid using ParallelDo. I have ~300 jobs that each take ~20 minutes to run and produce ~8 MB of data, and I am using a ...
0answers
49 views

### Having trouble understanding code to do formatting with MakeBoxes

Can anybody explaining this code? ...
0answers
44 views

### How can one combine multiple DensityPlot3D plots so they are all equally visible in the final plot?

How can one combine multiple DensityPlot3D plots so they are all equally visible in the final plot? Here is an example: ...
1answer
57 views

### Finding frequency of oscillation of an particle by Fourier analysis of the trajectory

I am trying to find the resonant frequency of a particle by Fourier analysis of the trajectory. Here is the data file. ...
1answer
88 views

### Plotting eigenvalues

I am trying to reproduce figure 10 in the linked paper. The authors have used Matlab bvp4c function to find multiple solutions for the system of ODE and then carried out the stability. Here is my ...
0answers
42 views

### How to find the derivatives from Solve after obtaining 6 complex solutions?

I have a 3x3 matrix. By setting the determinant to 0, I find the values of w in terms of ka and graphed the complex solutions. m, M, k, l are constants: ...
0answers
22 views

### Standard Error not right with Linear Model Fit [closed]

I tried using linear model fit according to the example found here https://reference.wolfram.com/language/ref/ConfidenceLevel.html I noticed that ...
1answer
36 views

### Force UnitConvert to display the proper unit prefix and return inexact quantities?

I'm experimenting with units: UnitConvert[1/Quantity[2.0, "GHz"]] 5.*10^-10s ...
0answers
48 views

### Obtaining the results of tagged cells in a notebook from another notebook

My objective is to read the results of several tagged cells in a notebook NB1 from another notebook NB2. Following the ...
1answer
257 views

### Integrate over a region

I am trying to calculate a integral over a region defined by But I dont really know how to do it, I dont know if I have to work in cartesian coordinates or polar coordinates. The function that I ...
0answers
80 views

### Code doesn't run on my system but runs in another system

I have an issue with Mathematica. I have some code and its answer. When I run the code on my system, it doesn't work. The person who wrote the code believes that is correct, and I agree. I tried to ...
0answers
45 views

### Converting an image of a plot to a plot?

Does Wolfram have the ability to (attempt to) convert an image of a arbitrary plot on the web, say: to its corresponding Wolfram representation (in this case:...
2answers
150 views

### Build a matrix from the coordinates of its elements and complete it with zeros

Suppose that I have a data set data (input): ...
0answers
44 views

### Comparing two methods of integration [closed]

Given two tolerances (like 10^-3 and 10^8), how can I compare accuracy of the two methods (explict Runge-Kutta and Adams) for the following system  ...
0answers
56 views
+50

### Loading Animation in Manipulate

I'm using Manipulate together with CreateDialog to run a ListPlot whenever I click on a ...
3answers
117 views

0answers
39 views

### StreamPlot hangs if streamPoints are outside the range specified

Is this a know issue? The following MWE works and gives plot immediately ...
0answers
19 views

### How to estimate parameters of TransformedProcess?

Let's say we have the following time-series. ...
1answer
48 views

### Retrieving the evaluation result of an Initialization Cell in a notebook nb1 from another notebook nb2`

I have a very long code in a notebook nb1 in which all the initialization cells are tagged. I have another notebook nb2 where I ...
1answer
54 views

### A single expression that performs substitution and simplifies a trigonometric form

I'm very new to Mathematica. I searched through the online documentation, but I don't understand why it realizes that $\sin(n\pi)$ for $n\in \mathbb{Z}$ is $0$: ...
1answer
31 views

### Extra white line in densityplot's output

How can I remove the white line in $y=0$? This is my code: ...
1answer
33 views

### How to solve an under determined system for a ratio of variables?

I have two equations in 3 variables a2, b1, b2: ...
1answer
61 views

### Track the location of of dot from noisy image

https://imgur.com/a/SnTYESG (subtraction between the image) https://imgur.com/a/ZdOS5wf (orignal image) From the original image, since my CCD camera is bad, I cannot really see anything. However, ...
1answer
41 views

### Writing code to produce continued fractions

I have been trying to create a continuing fraction to help prove the theory about any rational number: a/b being able to be written as a continued fraction where the remainders found in the Euclidean ...
1answer
33 views

### How to use FirstPosition in compiled function

I am trying to compile something similar to the following: test = Compile[{{data, _Real, 1}}, First@FirstPosition[data, _?(# > 0 &)]] However I get the ...
1answer
69 views

### Mathematica derivative not matching when I take derivative by hand

I want to take the derivative of this with respect to eta: fabc = 1/2 (-3 + 27/(2 + x)^2 + (1 - 1/(1 + (-1 + x) c[eta/cc])^2)/ c[eta/cc] + 2 Log[x]) Here I ...
1answer
43 views

### Plotting solution of an integral

I have used below code to plot the solution of an integral, but the code doesn't return anything. Could somebody please help me in this regard? ...
1answer
64 views

### Finding line that each n value is on

This code produces straight lines, I'd like to find which n values are on which of the lines: ...
2answers
26 views

Im interested in counting the number of operations required to evaluate a given formula. Let me give you an example. Lets say I have entered the expression $\dfrac{\operatorname{Sqrt}[\operatorname{... 0answers 16 views ### Estimate the Hidden Markov Parameter while keeping some of them are same How can I estimate the hidden Markov model while using the same value for some of parameters? First, let's get test data (sorry, messy!) ... 1answer 163 views ### Strange result for sum$\sum _{k=1}^{\infty } \frac{\sin (k (k-1))}{k}$In this sum over$k$Sum[Sin[k (k - 1)]/k, {k, 1, ∞}] the result still containes the summation index$k\$. ...

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