# All Questions

106 views

### Permutations and recurrence equation

First problem: I need to show all Permutations with length 4 of this elements {x, y, z, w, t} but with this condition: the element z mustn't be after element t. I ...
98 views

### Applying ReplaceAll to I (imaginary unit) [closed]

Why does I/.I->-I return -I but Exp[-I]/.I->-I yields ...
67 views

### Question about the third argument of Solve [duplicate]

I'm learning about derivatives. This is my code: ...
152 views

### How do I fit the parameters describing a 3D object so that it best resembles its projection seen by an observer at a particular position?

I have data which are the longitudes (l) and latitudes (b) for the vertices of the edges of a shape as it appears to an observer at a given location (i.e., as it appears on the observer's sky plane). ...
41 views

### InverseFourier of nested lists

last week I've got an Mathematica package that is using several inverse Fourier transforms on a data cube ($n\times n\times n$-array). I'm implementing the same functionality in C++ and tried to ...
237 views

### How can I use functions in file paths?

I'm very new to Mathematica and I'm trying to write into a file. I want to have a function in my file path. For Example: ...
201 views

### Study the possible coincidences of the three clock hands hour, minute, and second

Inspired by the very nice problem solutions of the problem of coinciding clock hands, I'd like to extend the question including a "second" hand. While it is obvious that all three hand can coincide ...
128 views

### Continuity of function-example

I'd like to examine the continuity of the following function: f[x_] := Limit[(n^x - n^(-x) ) / (n^x + n^(-x) ), n -> Infinity] I know that this function isn't ...
60 views

### How to generate commands which are very similar?

I have several data sets that I wish to interpolate and integrate like this: ...
116 views

### Kernel crash when using NIntegrate with Throw/Catch

Bug fixed in 10.2.0 My code is: ...
58 views

### series combinations

is there any possibility of displaying all possible series of the form: "1+/-2^2+/-3^2+/-...+/-n^2", where one can choose the sign before the each term and knows the numbers of the terms in the ...
283 views

### How to do multiple integral numerically?

I cannot calculate the following type of integrals numerically : $\int_0^1 dy \int_0^y f(x) dx$ $f(x)$ can be a complicated function. The problem is due to the fact that the upper limit of one of ...
374 views

### How to solve numerically an equation which contains numerical intergration?

F1[x_] := NIntegrate[E^Sin[y x], {y, 0, 1}] F2[x_] := Log[x] NSolve[F1[x] == F2[x], x] I want to solve the equation, but Mathematica don't solve it. ...
175 views

### Approximation of definite integral by parabolas

This question is related to Trapezoid approximation to definite integral. As promised, I am now asking about how to draw approximation of integrals by parabolas. I tried to modify MarcoB's code, and I ...
146 views

### Can I make a simple game in Mathematica?

Here is the game outline: $\hspace{2.5cm}$ There is one player. The player ($\mathscr{L}$) moves from node to node limited by the directed arrows. As the player moves, $\mathscr{G}_{\Huge\cdot}$ ...
83 views

### Manipulating a damped oscillator plot - plot does not show

I was trying to make an oscillation plot that could be manipulated depending on the value of $\beta$. The differential equation is below, and when I just plot the solution, it turns out to be the ...
560 views

### Performance problems in new Sequence functions

The new-in-10.1 Sequence* family of functions should provide newly optimized methods for handling sequence problems. Happily in some cases they do! For example ...
109 views

### Work around bugs in Summation, Hypergeometric function?

I'm so confused I don't even know how to phrase the question, so here's what's happening: I need an analytic form for this: ...
40 views

### Using ForAll in Maximize to define a bunch of conditions [closed]

I'm trying to do something very straight forward. The following maximization works: ...
196 views

### Subsets or Outer?

How do I generate all possible subsets of a list of positive numbers (with at least 1 of them), given that each of these positive numbers subvariates itself on its input value and its multiplicative ...
53 views

### Transform an XMLObject with XMLElements with empty attributes

I would like to transform a an XMLObject so as to replace all the non empty attributes of the XMLElements by empty attributes. ...
395 views

### Solving a complex logarithmic equation

I am trying to solve the following equation for $x$, with integer $n$. (1 - ((-1 + x)^E x^(1 - x) Log[x]^-E)^(1/(-1 + E)))/(-1 + x) == n
65 views

### Doing calculation on an imported data file [closed]

I have a data file which has been calculated from mathematica code and saved in test.txt, I need to import the data and do new calculation on it, here is the simple ...
248 views

### Is there a way to update Workbench 2.0 to recognize Mathematica 9, 10 and 10.1 functions?

Is there a way to add newer functions to a configuration file so that Workbench 2.0 is useable for development with 10.1? Also, are there changes that can be made so that Workbench 2.0 can be used to ...
124 views

### Different FourierParameters in each dimension for discrete Fourier transform

I have a query about the Fourier utility, that does discrete Fourier transforms. I am unable to find any information on whether different FourierParameters can be used in each dimension. This is a ...
143 views

### How can I avoid getting the message Solve::ratnz?

My function is ...
163 views

### Make the map of rivers and lakes of the country

As I understand,first of all I should to get the country's map and the river's list. To get country map is simple: ...
190 views

### How to change the plot range of on an axis other than z in a ListPlot3D [closed]

ListPlot3D[Table[Tan[j i], {i, 0, Pi, 0.1}, {j, 0, Pi, 0.1}]] I want to choose the plot range of y or x-axis so that for example only the right "hill" of the ...
427 views

### Converting timestamps into a decimal in minutes

I am importing a list of timestamps (hour:minutes:seconds) from a series of text files. I have the list: ...
225 views

### Curious solutions of x' = Sqrt(x), x(0)=4

Consider the solution of $x'=\sqrt{x}$, $x(0)=4$ using DSolve. ...
192 views

### How to rotate a complete graph without image rescaling while rotating

How do I rotate the following image? ...
61 views

### Splitting formatted output to multiple lines in a controlled fashion

Let's consider a slightly complicated expression in TraditionalForm: ...
33 views

### Why is DownValues releasing RuleDelayed's hold for Graphics? [duplicate]

I am trying to understand DownValues in regards to the evaluation of its output. Consider this: ...
68 views

### How to NDSolve a set of equations, one of which itself contains NIntegrate of a desired function?

How to NDSolve a set of equations, one of which itself contains NIntegrate of a desired function waited to be solved by NDSolve first? For example, ...
86 views

### How to simplify expressions by closing open inequalities?

Recently I have often acquired results which consist of combinations of 0, 1 and 2-dimensional (in)equalities. For instance, consider a very simple case with ineq1 ...
64 views

### Compute and Plot the element of a complex sequence

I'm new tho mathematica. I have a complex sequence ${z_n}$ with $z_0:=c$ $z_{n+1}=(z_n)^2+c$ for all $n\in N$ where c is some complex number, I need to plot the first 20 terms of this sequence ...
76 views

### NMinimize error: Nearest::neard:

I have this function GuessError, here's a plot assuming a single variable x, Plot[GuessError[10^x, etc..], {x, 8, 12}] , being etc some more variables which are ...
50 views

### Want apply “Position” in my list of Entities

I want apply "Position" in my list of Entities: Entity /@ GeoEntities[CountryData["Belarus"], "Lake" | "Canal"]["Position"] ...
75 views

### TSV import issue

I am having an issue importing a tab-seperated file properly. Most lines get split into elements based on the tabs but some don't: ...
77 views

### how to manipulate indices in a table/vector

Perhaps I'm missing something very basic. Could somebody guide me how to manipulate indices of a list. For example, if I have ...
111 views

### Handy dates conversion

I feel like something very basic is missing me, $dateformat = {"Year", "Month", "Day", "Hour"}; date = DateString[$dateformat] DateString["Date"] ...
147 views

### GCD of Table entries

This question is from a newbie, so please be gentle in thrashing if I'm missing something very basic. How can I use GCD on a matrix/vector entries stored as Table. For example, if ...
64 views

### Problem with double sum on the calculation of Ricci tensor

I wrote a program in Mathematica to calculate the Riemann and Ricci tensors (obviously, passing trought Christoffel symbols first), however just later I thought of calculating Ricci tensor directily ...
128 views

### Constructing lists in an efficient way

I have a list of functions and I want to separate them into two lists: a list that contains the functions that have at least one zero and a list that contains the functions that do not have ...
52 views

### NaNs in tabular data and import performance

I'm working with some data files that are just too large for Import. I tried using ReadList, specifying either ...
25 views

### Stopping resetting of linked locators in manipulate [duplicate]

I have found several solutions for linking locators (using the second argument for Dynamic) but they have the following problem: How do I keep the locators from resetting, when I choose something ...
36 views

### Edit Notebook options in version 10 [duplicate]

This is a follow up question to this one. I was closing a notebook without saving, Mathematica (10) showed me this dialogue: and I clicked "Save", when I re-opened the notebook I found this ...
338 views

### Count the number of regions made by Lissajous curve

How many disconnected regions does Lissajous curve divide the plane into? For example: Let g=ParametricPlot[{Sin[2 t], Sin[t]}, {t, 0, 2 \[Pi]}] The number ...