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votes
2answers
412 views

Lagrange multipliers code runs forever

I am writing a code for a Lagrange multipliers problem with three variables. My code looks like this: ...
0
votes
1answer
246 views

Why does initialization slow down manipulate in this case?

I'm trying to manipulate a plot of function with some parameters. The function is a long expression, so I tried to put it inside the Initialization options of ...
0
votes
2answers
2k views

Finding max value of each column of 4x4 Array

I have the following array in both MatrixForm and List form ...
0
votes
1answer
232 views

What is wrong with ContourPlot [duplicate]

Why does this plot have a big blank hole in it? ...
0
votes
1answer
587 views

FindFit: why do I get negative value as result?

I am trying fo fit a model to data using FindFit. ...
0
votes
0answers
108 views

Linear programming pivot

Here my object is purely pedagogical. When I was a student I hated linear programming because of the numerous operation we have to solve the simplest linear program. So now that I teach linear ...
0
votes
1answer
200 views

TabView resets to default when selecting data using Control object

I have 3 drop down boxes on one of the tabs in my TabView. Two of the drop down boxes results are used in a Select statement to ...
0
votes
1answer
58 views

How to stop Replace duplicating a list when using Table?

I have a 3 dimensional list of data pairs in the form: {{{{x11,y11},{x12,y12}},{x1...,y1...}},{{x21,y21},{x22,y22}},{x2...,y2...}}... etc Incidentally the data ...
0
votes
1answer
105 views

NSolve claims there are no solutions in Reals but finds them without restriction to Reals

When trying to answer this question I've discovered what looks like a bug in NSolve introduced in version 11.1.0. $Version <...
0
votes
0answers
56 views

Basics instead of VectorListPlot

J.M. kindly proposed ...
0
votes
2answers
196 views

Construct a pattern with an optional head

How can I construct a pattern that matches both f and h[f] without using the symbol f more ...
0
votes
1answer
471 views

Cannot import data into a notebook as a list of numbers

I have text file with a list of numbers separated by commas, which I would like import into a notebook to be called when the name ratevector is used. If I cut and ...
0
votes
1answer
67 views

$\LaTeX$ format copy problem [closed]

I need to write a $\LaTeX$ document from my functions developed in Mathematica. When I try to get a $\LaTeX$ form of the following integral ...
0
votes
2answers
193 views

Exctrating data information from a file.txt

I really did previous long search in the site and I couldn't find any answer that might help me. So I am asking it. I have the following data set, https://onedrive.live.com/redir?resid=...
0
votes
2answers
238 views

Large matrix: Finding eigenvalues and ordering it with respec to the highest coefficient of its eigenvectors

I have a 900x900 matrix to diagonalize. After diagonalizing it, I have a table of eigenvalues and eigenvectors. For convenience, I start with 3x3 matrix. ...
0
votes
3answers
79 views

Simplifying an identity from complex analysis [closed]

z = r (Cos[θ] + I Sin[θ]) I want Mathematica to return True when I evaluate ...
0
votes
3answers
356 views

how to take complex conjugate of a real variable

I have a function defined as follows: g[θ_] := 1/k (Exp[-I δ0] Sin[δ0] + 3 Exp[I δ1] Sin[δ1 Cos[θ] + 5/2 Exp[I δ2 (3 (Cos[θ])^2 - 1)) and I compute ...
0
votes
1answer
290 views

How do I declare that a variable represents a real number? [duplicate]

How do I tell Mathematica that a variable is a real number. I searched for this question here and in Google and nothing that was suggested seems to work for me. I must be missing something. My code is ...
0
votes
1answer
39 views

Error with Subscript in DialogInput

Writing: ...
0
votes
1answer
89 views

Mining for matching elements of sets with equal divisors

This problem is extrapolated from a problem that was solved on how to manipulate lists of set outputs as a union ( Equation Autogeneration ), where the concern now is how to mine for (or attain from ...
0
votes
2answers
90 views

How can I make my output to be added to an existing list?

v = {{0, 0, 0}, {1, 0, 0}, {1, 0, 1}, {0, 1, 1}, {1, 1, 1}} For[i = 1, i < 6, i++, For[e = 1, e < 6, e++ 1, Print[Mod[v[[i]] + v[[e]], 2]] ]] I ...
0
votes
0answers
626 views

Unable to Solve Two-Point Boundary Value Problem

I'm trying to solve the equation -u''[x] + ((x - k)^2 - en[x]) u[x] == 0 using the boundary conditions ...
0
votes
1answer
510 views

Phase Portrait Trajectories

How do I make a phase portrait which looks like the ones demonnstrated here? Not the fancy version where I can use the controls to change it, just a screen-shotted version of say a spiral point? Any ...
0
votes
1answer
2k views

Plotting a piecewise function [closed]

I'm having trouble plotting the piecewise function below. The only way I can replicate this function is using ...
0
votes
2answers
549 views

How can I fit a differential equation to experimental data?

I would like to add a fit to the following data. Here is the differential equation I am using. g=9.81 l=0.2 m=0.09 ...
0
votes
1answer
306 views

SolveAlways rejects inequality

I have two functions of x, f and g. f[x] = g[x] + 2, ...
0
votes
3answers
73 views

Sample the data with equal step size

I have the data below. I would like to sample with equal step size. For simplicity lets try unit step size. Here is the desired result. Find the first time exceed the unit time step, and take lower ...
0
votes
1answer
439 views

ParametricPlot3D etc. with parameters satisfying an implicit relation

I need some help on plotting the curve generated by a vector, given its three components as a function of two parameters, e.g. s1 and s2, whose range are known, and they have to satisfy a given ...
0
votes
0answers
30 views

Matrix equivalence over the integers

Is there any efficient way to tell whether two matrices $a,b$ are equivalent over the integers? That is, whether there exists some integer-valued matrix $c$ such that $$ a=c^Tbc,\qquad |\det(c)|=1 $$ ...
0
votes
1answer
81 views

What's wrong when I use ImageApplyIndexed?

I am reading a ebook called Basic image processing in Mathematica which can download free in the iBooks. In the page 114,it introduce a function ImageApplyIndexed...
0
votes
1answer
201 views

NIntegral takes long time

I am doing an Nintegral on Mathmetica. F[T,px,py,pz] is integrand with long expression. It has poles but with negative and positive infinity from two sides. Evaluate it at for example Eq[0.75], ...
0
votes
3answers
152 views

Saving many plots in files [duplicate]

I made a table of ten plots: Table[Plot[u[t, x] /. wws, {x, -10, 10}], {t, 0, 10, 1}] I want to save them all to my file system. I know, that I can save each ...
0
votes
0answers
172 views

Reducing a statement with Mathematica, step by step [duplicate]

Possible Duplicate: Get a “step by step” evaluation in Mathematica I have a list of inequalities combined with quantifiers. And Mathematica is able to reduce to simple statement with the ...
0
votes
2answers
284 views

Print expressions using local variables in Module without Dollar sign: is that possible

In a Module, I want to print the result of some data fit. I use something like this: ...
0
votes
0answers
69 views

How to obtain all minima? [duplicate]

If you Solve an equation, you obtain all solutions. But If you NMinimize a function, you only get one minimum. The question is:...
0
votes
1answer
672 views

“Moving” plot of a point moving in circular motion, in 3D

Maybe this is a tricky one! I want to have a 3D plot in Cartesian coordinates of a point moving in a circular orbit around x,y,z = 0. where the circular motion is only in the x,y plane. Has anyone ...
0
votes
2answers
10k views

How to pass a list as function argument?

I have the following function lFreqPhylo[a_, Q_, b_, p_] := Sum[Log[freqFunction[r[[p]][[i]], L[[p]][[i]], a, Q, b, {i, 1, nbranches[[p]]}]; The objects L, r ...
0
votes
1answer
379 views

Jacobian of nonlinear dynamic equations

As a supplementary to my question Calculate state-space model from dynamic equations, I have mixed linear and nonlinear dynamic equations, and want to linearize the nonlinear ones around an opperating ...
0
votes
0answers
52 views

Defining commutations rules over arbitrary matrix

I'm working with spin connections with Dirac gamma matrix commutator (I know, mathematica has specific ways to work with it), and I need to define the following rules; $[\gamma_{0},\gamma_{i}]= 2 \...
0
votes
1answer
286 views

Solving an ODE using the Taylor Method Help?

Not sure how to proceed after this... ...
0
votes
1answer
280 views

How to compute values only if input fields are filled?

In the following code how can I keep the DynamicModule from computing values if the input values are not all filled? If I don't specify default values it will show the code used to compute the values ...
0
votes
1answer
98 views

Finding the right DeleteCases pattern for <<199>>

I have a list in Mathematica with several items like <<199>> and <<104>>, I would like to get rid of them using DeleteCases, but none of the patterns I ...
0
votes
1answer
228 views

Turning a 2D 3 body problem into 3D not so easy? [closed]

I have programmed a 3 body problem, that can in theory work for more than 3 bodies. I apologize in advance for the length of the code that I posted, I don't really know how much one would need to help....
0
votes
1answer
119 views

How to get a list of vertices in a convex hull

I have the following convex hull: ...
0
votes
0answers
33 views

FindRoot for a transcendental function (PolyLog)

I am trying to solve an equation involving polylog using FindRoot, I am not sure how to give the initial guess as I want to solve the equation for a variety of parameters. Here is my code: ...
0
votes
1answer
127 views

Normal distribution plot construction

How would I go about creating a normal distribution graph with standard deviation given by P[x_] = -x*Log2[x] - (1-x)*Log2[1-x] and mean 6? I want to ...
0
votes
0answers
95 views

Matrix iteration failing after second step

I am calculating 11x6 matrix using different logics as in below code. Problem is in Do loop in below code where I have two different criteria to update matrix "fd". I am expecting logic in IF which ...
0
votes
3answers
161 views

DSolve taking a very long time with my ODE and not giving a useful answer

Evaluating with DSolve has taken ~50 minutes to complete when given this ODE: DSolve[y''[t] == Sqrt[1 + y[t]^2], y[t], t] <...
0
votes
1answer
132 views

looping in mathematica for using the current value as initial state of next value [closed]

i have some initial state $psi[x,t]$. I perform some operation on it and store the value in another state $pi1[x,t]$. Now on the next step i have to use $psi1[x,t]$ as initial state and perform the ...
0
votes
1answer
209 views

Colors on a 3D curve not working

I'm having troubles applying colors to a simple 3D curve plot. Here's the code : ...

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