# All Questions

61 views

### Manipulating of non linear differentials equation

I want to manipulate non linear differential equations $\dot{x}= x + g\, xy\quad \dot{y}= 1-2x^2-g\, y^2$ where g as parameter.but I don't get any curve on display. Plz help me
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### Plotting the solution of a Chini differential equation

In DIFFERENTIAL EQUATION SOLVING WITH DSOLVE by D. Kapadia, there is a Chini differential equation : sol = DSolve[x'[t] == 5 x[t]^4 + 3 x[t]^(-4/3), x[t], t] ...
116 views

### Getting Area of a region transformed by GeometricTransformation

I tried this: Clear[b1, b2, A, p] b1 = {-1, 1}; b2 = {1, 1}; A = {{2, 1}, {-1, 1}}; p = Parallelogram[{0, 0}, {b1, b2}]; Then drew this: ...
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### Plotting a dataset and its fit dynamically

I have the dataset ...
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### Can you unpack a list of values into variables in a With expression?

For instance, if I am trying to draw a graph with 5 vertices labeled a through e, and I want to draw edges connecting a and b, a and c, a and d, a and e, b and c, b and d, and c and e, I would run the ...
154 views

### Replacing elements in lists of a nested list

I have the following nested list ...
39 views

### Create movies from data files [closed]

I've done some simulations of a trajectory of a particle and I have that trajectory saved in ".dat" files. Now I want to make an animation/movie and save it as GIF to include it on a presentation. I ...
118 views

### Solving Partial Differential Equations using NDSolve

I'm trying to solve the following partial differential equation: With the boundary conditions: I could use another way to resolve this, like the finite volume method, but after I solve the ...
54 views

### Problem with Volume and Parallelepiped [on hold]

This worked (copied from the documentation), and gave correct image with Graphics3D. R = Parallelepiped[{0, 0, 0}, {{1, 0, 0}, {1, 1, 0}, {0, 1, 1}}]; Volume[R] ...
39 views

### Approximation number and remove the extra numbers [on hold]

I want to approximate a number and capture it in a variable, but when I want to work with that variable the extra number that I wanted to remove in approximation gets involved. Can any one help me? ...
51 views

### How to take a list and build sets of 2 elements without duplicates?

I am new to Mathematica so the answer to this question is probably easy. I have a list of 2D-points in the form {{x1, y1}, {x2, y2}, ...} Then I have a function that will take two points and test ...
56 views

### Defining a function that depends on the length of a number and the $n$-th digit

I have defined the functions F[i][x] for i={1, 2, 3}.. I want to write a number that has only the characters 1, 2, 3, and I want ...
64 views

### Aguilera-Perez Algorithm of $nD$ rotation matrix [on hold]

I want to compute a general $nD$ rotation matrix which corresponds to a rotation by an angle $\theta$ around an $(n−2)$-dimensional subspace. I found the Aguilera-Perez algorithm in their paper: ...
105 views

### Ballistic motion of a particle giving trouble at high drag values

The following code: ...
67 views

### Form with FormFunction problem

I've this form: f[a_, b_] := a + b; form = FormFunction[FormObject[<|"a" -> "Number", "b" -> "Number"|>], f[#a, #b] &]; form[] How I can ...
34 views

### How to make a Dataset a Vector or Matrix? [closed]

I have a Dataset containing some data. I would like to extract single columns as vectors so that I can perform vector and element-wise operations on them. Is this possible in Mathematica? For ...
260 views
+100

### Symbolically prove that two expressions are identical

I encountered this problem when trying to reproduce the result of this paper. (The relevant parts are all included in the preview i.e. the 1st page of the article. This link is just given as ...
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I have a physics simulation program which I run through a terminal window (I use a Mac) as shown below: user$programName inputfile.ele I would like run a ... 1answer 110 views ### Solve returns empty list I want to solve these equations but Mathematica gives no answer. ... 0answers 34 views ### VectorPlot3D in cylindrical coordinates I am using VectorPlot3D to plot fluid flows (in the form of a velocity field), however, I go through quite an involved process to convert flows in Cylindrical ... 0answers 56 views ### How to Extract Scatter Plot in Continuous Graph by Constant Piecewise Velocity? [closed] Condition: inverse problem in extracting scatter plot without metrics (only relative points) from the continuous time-potential data where points are distributed with constant piecewise velocity ... 7answers 465 views ### how to get$n$equidistributed points on the unit sphere We can get$n$equidistributed points in the unit circle using CirclePoints. But how do you get$n$equidistributed points on the unit sphere(surface of a ball)? ... 3answers 117 views ### How can I draw ternary plot by these data? I have these data and want to draw similar fifures in mathematica. any one can help me? ... 3answers 98 views ### Expanding a matrix in a set of matrices Consider a vector$a=\{a1,a2,a3\}$. I computed$e^{i a\cdot \sigma}\qquad \sigma: {\rm Pauli\ matrices}$and then applied the command ExpToTrig. Now I want to expand the above result in terms of ... 2answers 180 views ### Samuel inverse graphing calculator Samuel Inverse Graphing Calculator (http://www.xamuel.com/inverse-graphing-calculator.php) is a amazing tool. Whichever be your language, you can transform a sentence in an equation. I hav try with Yo.... 1answer 120 views ### Solving 2D Laplace equation for irregular boundaries [on hold] I want to solve Laplace equation in 2D with$x$and$y$coordinates with the boundary conditions$V(0,y)=-180$;$V(x,0)=50x-180$;$V(x,6)=50x-180$;$V(453.595-\sqrt{450.05^2 - (y - 3)^2},y)=0$The ... 3answers 722 views ### How to create this spikey in Mathematica? I came across this post while messying around the StackExchange mobile. I think this thing can be easily done by Mathematica as well but I'm not an expert in geometric field. Can anyone give some ... 2answers 150 views ### How to do this 3D grid drawing? [on hold] The idea is to make axes 3d, with a more subdued in black mesh, and shafts with their respective numbers with a maximum of 10 in each (black to print after the size of half a sheet craft, vine also ... 4answers 170 views ### Efficient way to compute a complement while respecting multiplicities [duplicate] Suppose I have list2 which is a subset of list1. I want to get a res by deleting an element ... 0answers 61 views ### ArrayPad with vectors [on hold] I would like to pad a nested list like M = {{{a, b}, {c, d}}, {{e, f}, {g, h}}} with some constant "vector", e.g. {0, 0}. ... 1answer 79 views ### Double Sorting a Matrix Say I have two matrices {{0, 1, 2, 2}, {2, 1, 0, 2}} and {{2, 1, 0, 2}, {2, 1, 2, 0}} I then sort by the first row ... 2answers 48 views ### How to plot data with different colors (or symbols) depending on a condition [duplicate] Let's consider a simple example. I want to plot a function on [0;2], depending on a condition: if x<1, I want to plot ... 1answer 72 views ### Drawing a circle with radius = 40 miles around Bunnell, Florida The following works: ... 1answer 51 views ### Putting plots and graphs on a word document [duplicate] Is there a way to copy and paste or save an image of a graph into a word document? 0answers 50 views ### Mathematica treating a system of 1st order nonlinear ODEs as a system of DAEs I'm trying to use NDSolve to solve a system of 1st order nonlinear ODEs. The system of equations is way too long to post here, but it is in the canonical form:$x_i'(t)=f_i(t,x)$. My problem is that ... 1answer 205 views ### Mathematica implementation of Zeilberger's algorithm (previously done in Maple) I have this Mathematica code: ... 1answer 58 views ### How to make the variables in$init.m$not impact the autocompletion The autocompletion is very convient in Mathematica,but it will make one annoying sometimes when you have a ton variables.I give a scene I encounter.I usually make ... 3answers 103 views ### how to update elements in a matrix with position identified in a list I am new to mathematica. Could you pls help me on how to write this: I have a$5\times 10$matrix, for example, ap = ConstantArray[0.001, {5, 10}] I have the ... 1answer 57 views ### How to make the$ModuleNumber dynamic in a string

This code can run normally ...
62 views

### Importing Data to interpolation

I have an external file in extension XLS with looks as follows: This file can be obtained by the link below: Velocidade Angular With certainty this file is generating a list inappropriate for the ...
35 views

### How to parallelize a sequential program? [on hold]

I asked this question and I got good answers, but now when I try to make the computing in parallel with this command ...
98 views

### Differential algebra package in Mathematica

Is there any equivalent of Maple's differential algebra package in Mathematica? In particular, the Rosenfeld-Groebner algorithm has been implemented?
30 views

### Differentiation and series expansion of dot product - inconsistent results

If I differentiate a dot product, I get the result I expect D[a.b[x], x] (* a.b'[x] *) However, a series expansion of the same expression gives a very different ...
139 views

### How do we draw some auxiliary lines for typical values of the function in a 2D Plot?

I want to draw some auxiliary lines for typical values of the function in my graph like these blue dashed lines: Also, I want to put the values of the lines by the lines like above one. Do you know ...
15 views

### polarized hodge structure [closed]

With the notations in the picture blew, we define the classifying space D for the polarized hodge structures is the set of all collections of subspaces of H, how to deduce the conjugation relation?
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A fairly simple experiment, I am trasponsing an identitiy (3x3) matrix, and I got a weird result. I tried also CUDADot and works as expected. The code I used: ...
114 views

### Automatically add debug contents to a program

Sometimes I'll use Print[1] or Print[n] to debug in a long loop, but it's really a boring job to add these sentence by sentence ...
69 views

### How can I find the Quandl codes for metals?

Probably not the right site to ask this, but how can I find out the Quandl codes for different commodities? For example, gold against USD? Tried "CURRFX/XAUUSD", ...