All Questions

0
votes
0answers
3 views

Mathematica integration error

Integrate[Integrate[Abs[Exp[2*Pi*I*x] + Exp[2*Pi*I*y]], {x, 0, 1}], {y, 0, 1}] yields 0 as result. This cannot be correct, ...
0
votes
0answers
11 views

Removing non-word characters in certain parts of a string

I would like to ask how I can remove non-word characters from a string, but only in certain cases. I have read this article, so I know how to get the words out of a string. My text is however a bit ...
0
votes
0answers
2 views

Exporting animated gifs; “AnimationRepetitions”->1 doesn't work!

I'm trying to export a table of graphics into a gif animated file with just one repetition. Export["C:\Race.gif", t, "AnimationRepetitions" -> 1] It doesn't ...
0
votes
0answers
8 views
0
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0answers
15 views

How could I upload a XLS file to Cloud and then plot it?

I want to upload a file to the Wolfram Cloud and plot the list: So I use the following code to check its head at the beginning: ...
0
votes
0answers
10 views

formulate a condition that function f(x,y) must hold in order to be considered as “associative” [migrated]

Let f(x,y):{0,1}^2->{0,1} be a Boolean function. Answer the following "warm-up" questions: a. Prove or dispute: The function f can be one-to-one. b. Formulate a condition that function f(x,y) must ...
1
vote
3answers
38 views

Computing a map between two lists

What I want is a little difficult to explain. So I try to it with an example. I have 2 lists, each of which has $(n-1)^2$ elements. Each element is an integers between 0 and $n-1$, inclusive. For ...
0
votes
0answers
29 views

ball lens minimum aberration

this is my project(simulation) a set of parallel rays goes trough a ball lens(circular lens).because of spherical aberration refracted rays will not meet in a single point.find the distance which ...
0
votes
0answers
20 views

Faster way to build a set height in the z-axis direction in the thickness plane graph?

test image can be a Plot, ParametricPlot, RegionPlot, ContourPlot etc.!! ...
2
votes
1answer
13 views

Put/Get don't accept a string-valued expression as filename [duplicate]

I'm trying to do the following with an expression: filename=StringJoin[{"myfile", ToString[someNumber],".m"}]; expression >> filename; But mathematica ...
0
votes
0answers
38 views

Curve fitting of a list

I have list obtained using an integrals. I want to obtain an analytical formula that fits my list using curve fitting. Please suggest a simple analytical structure that fits my curve. ...
0
votes
1answer
24 views

Histogram from a list of matrices

I have a list of around 100 matrices, that looks like this ...
2
votes
2answers
64 views

Grid lines extending too far

The grid lines in the following plot extend beyond the data and, in particular, into the numbers along the axis. ...
0
votes
0answers
17 views

How to automatically Import, Name and Export multiple images? [duplicate]

Sorry for the very basic question but I'm really new to Mathematica. I have a directory(myDataDir) full of images (myImage1.tif, myImage2.tif...) I have a piece of code (let's call it ...
0
votes
1answer
44 views

Wrong Definite Integral result

When I calculate the definite integrate of (a+bt)*cos(nt). Integrate[(a + b t) Cos[n t], {t, t1, t2}] MMA gives a correct answer: ...
1
vote
0answers
34 views

Open Mathematica in text editor displaying just the code

I need to translate some code to another language and I don't have a working copy of mathematica. All I need it to do is display the code exactly as it would in mathematica, without any of the fancy ...
0
votes
1answer
30 views

Using RegionPlot3D to make a cone under restrictions

I have to plot a cone that satisfies this statement: Use the RegionPlot3D command to draw a picture of a cone with its point at the origin. The other end of the cone is a circle with radius 5 ...
0
votes
0answers
21 views

Using real numbers gives suspicious result

In the code below when I use a real number for number 4 in the exponent in the irf function, it returns wrong result. ...
9
votes
2answers
246 views

How to wrap a plot around a circle?

Consider the code a = Table[BesselJ[i, x], {i, 0, 3}] Plot[a, {x, 0, 20}, Axes -> False] producing I'd like to transform the plot into a circle. In other ...
-1
votes
0answers
30 views

How to replace colours in an image from Wolfram Alpha [on hold]

I recently saw this post on the Wolfram Blog. I have tried doing the exact same thing on the blog but I'm not getting the same results. I'm getting this image: Instead of this: I'm also ...
-1
votes
0answers
30 views

Proof that $(1+\epsilon)^n = O(n\epsilon)$ [on hold]

How to prove that $(1+\epsilon)^n = O(n\epsilon)$ ? So far I proved the following: By the binomial, $(1+\epsilon)^n > n\epsilon$ Also $\epsilon^n$ = 0 when n-> infinity.
0
votes
0answers
58 views

Problem in Plot at start [duplicate]

The derivative can be used to calculate roots. However the same function cannot be plotted.The error is at start point of domain: ...
2
votes
1answer
29 views

Mapping also for one element (or telling it how to do so if head got changed)

Some code generates a polynomial, and has the form: expr = Plus[a[i],b[i],c[i],d[i]] I need to apply f to each term. To do ...
0
votes
0answers
35 views

Handling Accuracy and Simplifying

I have the following problem. I have a system of non-linear equations that I log-linearize around a certain point, let's call it point A, using a function that I ...
4
votes
1answer
50 views

Functional defined Ticks of LogLinearPlot does not work

version 10 $Version "10.0 for Microsoft Windows (64-bit) (June 29, 2014)" Consider three cases in LogLinearPlot's ...
6
votes
2answers
206 views

Is there an easy way to use Matteo Niccoli's perceptual color maps for 2D plots in Mathematica?

I have been using the ubiquitous Jet color palette for 2D plots for some time now, and don't really care for it. Then I came across the series of blog posts, The rainbow is dead...long live the ...
3
votes
1answer
56 views

Remove redundant parameters from equation

I have random expressions like (b1 x + b2 x)/(b3 + b4/b5 x) + Sin[b6 x] where $x$ is a variable and {b1, ..., b6} are parameters to be fitted. This expression is ...
0
votes
0answers
39 views

Is There a Reliable Way to Solve the Following Non-linear PDE Using Mathematica? [on hold]

I'm trying to solve the following non-linear PDE using Mathematica. Indeed I should write my own codes, but I didn't do it for two reasons: 1. there seems not to be any reliable way to "discretize" a ...
1
vote
1answer
61 views

handling division by zeros and line equations

today I was writing a code which takes some line equation and a circle equation,finds intersection points that are on $II$ and $III$ quadrants,draw a tangent line to circle from that point and then ...
0
votes
0answers
58 views

Mathematica ERROR [on hold]

I would like to know what your opinion is about this paper and the discovered errors: http://www.ams.org/notices/201410/rnoti-p1249.pdf I also like mathematica, but nevertheless a statement of ...
1
vote
1answer
26 views

problem on returning value of function as a list using if

today i was writing a function for my project using mathematica that gives a line equation in form of $y=mx+b$ and a circle equation in form of $x^2+y^2=r^2$ and finds the intersection point which is ...
0
votes
0answers
40 views

Empty Graph for Absolute Function

I wanted to plot the following equation: Plot[((x/7)^2 Sqrt[(Abs[Abs[x] - 3]/(Abs[x] - 3))] + (y/ 3)^2 Sqrt[(Abs[y + 3 Sqrt[33]/7])/(y + 3 Sqrt[33]/7)] - 1) (Abs[x/2] - ((3 ...
0
votes
0answers
29 views

Series expansion of InterpolatingFunction obtained from NDSolve

I am trying to obtain a series expansion of the numerical solution of a differential equation. I encounter difficulties going beyond first-order expansions which I believe might be due to my inability ...
2
votes
3answers
83 views

Partitioning time series

I have a time series dataset I'm trying to plot by Year: ...
0
votes
1answer
39 views

Why don't these assumptions result in further simplification?

I'm trying to simplify an expression, which has a factor of $\lambda(\lambda-1)$, where $\lambda$ may be either $1$, or $0$. So I try: ...
0
votes
1answer
31 views

Why can't I import a file in the init.m file?

I would like to have some data read in every time the kernel starts, but it doesn't seem to work. Say I have a CSV file I want to have read in, for example I use: ...
5
votes
3answers
108 views

How do I display the parameter value in animate, similar to how it's done in manipulate?

When I use manipulate, there is a 'plus sign' in the top right that, if I click on, shows my parameter value. I used animate, because other posts suggested that it solved other issues I had, but now ...
13
votes
0answers
115 views

DumpsterDoofus's captivating generative art

How can I render these beautiful images that DumpsterDoofus posted?
1
vote
1answer
55 views

Changing the Ticks in LogLinearPlot for representation pH values

I need to change the ticks in the xaxis for representation pH values, but the ticks are not dispersed along the range of xaxis. Another question: why the vertical line defined with Epilog is not ...
0
votes
0answers
10 views

Changing variable value via loop [on hold]

Just a quick question, I have the following code: Do[{ Mtest = 2; Mtest = Mtest + 0.1; Print[Mtest] }, {n, 1, 5}] What I hope to do is have it loop 5 ...
2
votes
1answer
35 views

Is there a simple function identify the sign of an expression given constraints

I'm looking to find a simple function that can identify the sign of an expression given a set of constraints. I have looked around and do see that there is a few threads on this but I'm not sure I ...
0
votes
2answers
65 views

How to solve ArcSinh equation for many differents parameters?

I am totally stuck trying to solve the equation below (1/2) x Sqrt[1 + 4 a^2 x^2] + ArcSinh[2 a x]/(4 a) == d Where a and ...
3
votes
1answer
441 views

Over 30mins to generate the first eigenvector?

Is it normal for Mathematica to take over 30mins to try to compute the first eigenvector of a 100x100 matrix? The matrix is reasonably sparse - about 90% of the cells are 0s and each column sums to ...
1
vote
1answer
60 views

How to form a variable from matrix elements

I have matrix with n rows and 2 columns, say m = {{x11, y12}, {x21, y22}, ..., {xn1, yn2}. Now, I want to form three new variables for example: ...
0
votes
0answers
28 views

Pick out element from array [on hold]

I have the $3\times 3 \times 3$ array: ...
0
votes
0answers
27 views

How can i insert mathematica graph in eps format into word file without lossing a right vertical line? [on hold]

How can i insert mathematica graph in eps format into word file without lossing a right vertical line? if any one know please help me
0
votes
0answers
67 views

Can not understand the code to plot Fourier Series approximation of the line

I'm reading the CDF file from Making Formulas… for Everything in wolframalpha blog. When I step into In[9] and In[10], I'm fully confused. Who can tell me what does the two functions mean? The ...
0
votes
0answers
42 views

Improve on timing of NMinimize

I got a little performance problem with the function NMinimize (it takes mathematica approximately 10 minutes to compute the results). Here i s my sample code: ...
1
vote
3answers
62 views

Randomly changing matrix entries

1.Write a block of code that generates a 4x4 matrix with randomized real number entries each between 0 & 1, then selects 3 matrix entries at random, and finally replaces these 3 entries with a ...
0
votes
0answers
24 views

Nested For loop in Mathemaitca for solving FDM problem

I am solving a FDM problem in Mathematica My equation is d[Rho]/dt + beta*Rho= alpha*q dq/dt + v*dq/dx +alpha*q= beta*rho nx = nt = 5; ...

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