0
votes
0answers
56 views

Solution Branch Switching of Quartic

Im using a closed form solution for quartic equation. In the quartic equation, there are parameters that are being varied and therefore the solution changes depending on these parameters. The ...
1
vote
1answer
41 views

plot filling using blend and y value

I want to plot say Sin(x) with colorfilling. but I want the colour to be a gradient between white and red. When Abs[sin(x)] is maximum I want white, when its minimum I want the filling to be red. In ...
3
votes
1answer
228 views

Filling using colors rendered corresponding to the difference between two curves

Suppose there are two curves f1[x] and f2[x], and we want to fill the area between them using colors corresponding to the vaule ...
3
votes
1answer
42 views

Reals in Range; unexpected result for non-standard Precision

I think I have encountered advice against using inexact numbers in specifications of ranges and iterator many times. I don't think I ever saw an example of unexpected results though, but today I found ...
2
votes
1answer
126 views

Derivatives of functions with arbitrary number of variables?

I am trying to define a function f[x1,x2,...,xn] with n integer but not specified. And then I would like this funktion to behave ...
1
vote
2answers
83 views

List Operations: how to combine two lists (pattern given)

Two lists (matrixes) are given: a = {{x1, y1}, {x2, y2}, {x3, y3}}; b = {{u1, v1}, {u2, v2}, {u3, v3}}; Expected return: ...
1
vote
1answer
71 views

Dealing Repeated pattern in StringReplace

A problem about StringReplace When I'm running into this problem possible [bug] ...
0
votes
1answer
47 views

Want to display a animation necklace when updating a list of suggestions from an inputfield search

I have an InputField search that provides search suggestions, but I want an animation necklace to be displayed while the search is 'busy'. I would also like this to be done using Dynamic rather than ...
1
vote
1answer
79 views

Transform linear system into a matrix form

I have a system of linear equations in variables $A_n$ of form: $$ \sum _{k=-K}^K h_k A_{n-k} J_{n-k}\left(\frac{(1-i) \text{$\eta $Sqrt}(n-k)}{\sqrt{2}}\right)+A_n\left(\frac{(1-i) \eta ...
0
votes
0answers
33 views

DateListPlot not showing any ticks

With a vector dates (in DateList format), and a vector data that has the same length as ...
1
vote
1answer
58 views

Switching to CloudObject`Private`

I shut Mathematica done, then restart it. The image shows all that I do. I have done nothing else. Can anyone explain what is happening to me? The complete code is: ...
3
votes
2answers
219 views

Bessel derivatives

I tried to expand BesselJ[k,x] function into a Taylor series with Series command. Here both ...
3
votes
0answers
66 views

Detect touching particles in image

I have a picture of glas spheres. I want to calculate different properties of these spheres such as circularity, size and count them. I have managed to fill the white centers of the particles to ...
1
vote
0answers
159 views

What summations can Mathematica do? [closed]

I was very pleased to discover that Mathematica could do this summation and produce a symbolic result. ...
15
votes
3answers
2k views

Relative paths for portable notebooks in Mathematica

I cannot find how to use relative paths in Mathematica. My directory structure is simple. ...
0
votes
0answers
26 views

Multivariable Integrate [on hold]

Why won't Integrate[r^3, {r, 0, a - a/b z}, {z, 0, b}] work? The integral symbol method works though:
1
vote
2answers
63 views

Plotting NIntegrate

Plot[E^(-0.5 x) NIntegrate[Cos[t] E^(Cos[t] + 0.5 t), {t, 0, x}], {x, 0, 40}] Mathematica evaluates this integral for each point, which takes a long time. It is ...
0
votes
0answers
20 views

Insert Citation dialog comes up empty

I'm using Mathematica 10 with Endnote X5 on Windows 7. When I click on "Insert> Citation> Bibliographic Reference" command (while the cursor in Mathematica is in 'text' style mode, Alt+7) Endnote ...
3
votes
1answer
239 views

Principal Components - how to obtain linear transformations?

I have a list "xlsf" with 6 columns and 1200 rows for PCA analysis. The PrincipalComponents[xlsf] gives the following: "The principal components of matrix are ...
2
votes
1answer
100 views

Numerical evaluation of ChebyshevT

When I evaluate the following Chebyshev series of the first kind in two different ways, I get two very different results: ...
23
votes
3answers
3k views

Standard errors for maximum likelihood estimates in FindDistributionParameters

I am trying to fit a non-standard PDF to data and FindDistributionParameters works great, and gives me the parameters of the distribution back using maximum ...
0
votes
0answers
15 views

Problem of importing some special characters in HTML

content of the html file is as follows: <p> 被尊称为&ldquo;高贵的&rdquo; </p> method1: ...
1
vote
2answers
212 views
0
votes
0answers
53 views

Asymptotic forms of Bessel function

I want to replace Bessel functions by asymptotic forms, so the question is: can I find the best ones with help of Mathematica? And if it's possible, how can I do it? Update How can I get with ...
0
votes
0answers
136 views

Optimization method L-BFGS-B

I am comparing a result of optimization using R and Mathematica. Mathematica (NMaximize) has found a significantly better (global optimum) result then R (using ...
0
votes
0answers
37 views

All contours aren't shown in ListContourPlot

I want to plot the contours of a data set which when plotting in 3D looks like this: When I plot the contours as ...
3
votes
0answers
165 views

Nonlinear FEM and FindRoot

I'm trying to develop a kind of nonlinear FEM application using mathematica to solve a bvp like the following: $$ \gamma(u') ~u^{iv} + 2 \gamma'(u') u''' u''+ u''^3 = f(x) $$ where $u = ...
1
vote
1answer
86 views

Is there a LogBeta function like the LogGamma?

In a computation, I need Log[Beta[alpha+j,beta-j+n]] of some kind. Is there a LogBeta function built-in to avoid any under/over ...
5
votes
1answer
102 views

Number of divisors visualized with the QPochhammer function, how improve performance of code?

I have this code that originally is Jeffrey Stopple's code for the Riemann zeta function in the complex plane. Because I discovered yesterday that the number of divisors can be generated with the ...
3
votes
1answer
222 views

Approximate $h$ in $F(\theta)=\sin \theta \int_{-L}^{+L}h(z)e^{-ikz\cos \theta} \,dz$

Consider $$F(\theta)=\sin \theta \int_{-L}^{+L}h(z)e^{-ikz\cos \theta} \,dz$$ $$|z|\le L$$ $$0 \le \theta \le \pi$$ By having knowledge of $F(\theta)$, how can one approximate $h(z)$? In ...
2
votes
4answers
89 views

how to cancel arbitrary term in fractional formula

I often encounter this kind of problem that I want the fractional formula to be looked like the way I want it to be. For example, this one $$\frac{R^2 \left(g m_1-g m_2\right)}{J+m_1 R^2+m_2 R^2}$$ ...
3
votes
3answers
80 views

Identifying locations of entries in an array

If I’ve got a big array displayed in Mathematica, is there a way for me to select a particular location on the screen and have Mathematica tell me “You’ve selected the entry in row 137 and column 92” ...
4
votes
1answer
116 views

Solving a chemical system using NDSolve

I have to solve a set of coupled differential equations and am not sure how to proceed. It is a model of a chemical process where I'm interested to find the species concentration as $r$ varies. For a ...
7
votes
4answers
453 views

MovingAverage to include the average of the first and last elements in a list

Is there any way to take the average of pairwise elements in a list? Example: Given the list list = {a,b,c} I'd like to generate the list ...
8
votes
3answers
547 views

What is wrong with my expression for compiling?

Following code was translated from a snippet matlab code. Without compiling it worked slowly. I want to compile it, but am getting a numerical error. How do I compile this in a correct way? ...
-3
votes
0answers
78 views

A polyhedron convex test

I want to write a test function to see if this polyhedron is convex or not: ...
2
votes
1answer
501 views

Use Euler method to solve differential equation

Use Euler's Method or the Modified Euler's to solve the differential equation ${dy/dt=y^2+t^2-1, y(-2)=-2}$ on $[- 2, 2]$. Take h = 0.2 (...
2
votes
2answers
435 views

Plotting several numerical solutions plus the analytic solution of ODE in one plot

I want to be able to plot several numerical solutions of an ODE, plus its analytical solution in one plot, in order to see how the numerical solutions converge towards the analytical one with respect ...
1
vote
1answer
862 views

Euler's method for system of differential equation

I need to program Euler's method to solve a system of two diffferential equations of first order. Fist, I have programmed the Euler's method for just one differential equation: ...
5
votes
1answer
629 views

NestList and Euler's method

I am new to mathematica and so just experimenting with various programming constructs. Recently have been looking at NestList and how I could use this to implement ...
0
votes
0answers
47 views

How to change dimensions of a matrix? [on hold]

I have two sets of data that I'm working with, both of which should be 1024 x 1024 matrices (they're from the same instrument). However, when I go to manipulate them, the dimensions of one are read as ...
1
vote
2answers
156 views

Complex numbers from two arrays with Real and Imaginary parts

I have two arrays, containing the real and imaginary parts of a list of complex numbers. Re = {{Re_number1},{Re_number2},...} Im = {Im_number1},{Im_number2},...} ...
3
votes
1answer
95 views

Precision of NIntegrate

At the moment I am considering a "difficult", highly-oscillatory integral in Mathematica. It calculates the integral without any complaints. However, I am also trying out a numerical method with which ...
0
votes
1answer
191 views

How to export figures with normal spacing in texts?

My OS is Ubuntu 14.04, and I use MMA 10. I export a figure ploted in MMA to a pdf file and then import the pdf in Latex, here is the sreenshot As you can see, the spacing in the text is odd. But ...
1
vote
2answers
62 views

Extracting subtree for a TreeForm

How can I extract an entire subtree from a TreeForm starting from a specific point of the tree? Because with Extract or Part you can take only that specific point...
3
votes
3answers
126 views

How to assign symbols to functions

Several functions work with symbols in MMA: Take for example Part: l1=l2=Range[4]; l1[[3]] (*3*) l2[[4]] (*4*) I want to make ...
0
votes
1answer
37 views

Encountered non-numerical value for a derivative at x==0 [on hold]

this may be a duplicate question but I still don't understand how to get around this problem after reading through other posts. I'm trying to solve a differential equation ...
1
vote
2answers
77 views

Plot3D and NIntegrate issues

f[x_, y_] := 2*x - y Plot3D[f[x, y], {x, -1*Sqrt[4 - y^2], Sqrt[4 - y^2]}, {y, -2, 2}] NIntegrate[f[x, y], {x, -1*Sqrt[4 - y^2], Sqrt[4 - y^2]}, {y, -2, 2}] I ...

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