# All Questions

322 views

### How to sum over duplicates?

I have a list of the form: {{1, 0, 1}, {2, 1, 2}, {1, 0, 3}, {2, 4, 2}, {2, 1, -1}, {1, 0 ,0}} that I would like to sort such that I calculate the sum over the ...
340 views

### Importing Quicken Tab Delimited .*TXT File and plotting

I am using Mathematica 7 to try and plot my quicken data file. I have exported my quicken file as a .*TXT and have made zero changes to it. I want to do a ...
137 views

### How can selection of delimiter matches be disabled?

I often preemptively match delimiters. As a simple example, I'll type Import[], then left arrow, then "filename". The problem ...
232 views

### How to print preview a selection?

When printing (file->print...) there's the possibility of printing just the current selection. This is useful for printing just a couple of cells, or some chapters. The file menu also has Print ...
473 views

### How to insert a link to a generic file, in the middle of a text style cell/paragraph?

It is easy to insert a Hyperlink to a notebook file, or to an internet address, in the middle of a text style cell (Ctrl+Shift+H or menu: Insert->hyperlink). Trying to create a hyperlink to a file ...
208 views

### Why Trace[] shows some internal warnings on a standard Plot command in V9?

For fun, I like to use Trace with option TraceInternal->True to see if I figure how some of the commands work internally. I ...
193 views

### Break[] inside ColorFunction

f[x_?NumericQ]:= (Do[Break[],{i,1,2}];x) Plot[x,{x,0,1},ColorFunction->(ColorData["Rainbow"][f[#]]&)] Break::nofwd: No enclosing For, While, or Do found ...
8k views

### Are you interested in purchasing David Wagner's “Power programming with Mathematica”?

I recently contacted McGraw-Hill to see if they have a mechanism in place for printing out-of-print books that are still of interest. Specifically, I asked about "Power programming with Mathematica" ...
1k views

### Logarithmic scale in the legend of a ListContourPlot

Is there a way to use a logarithmic scale in the colour legend of a ListContourPlot? The contours can be logged by taking the ...
287 views

### How can I superimpose points or disks on an image at specified coordinates?

I have a TIFF image of 640 x 640 pixels, over which I would like to plot a list of points or disks of small radius. I have been testing different alternatives and I found ImageCompose command. ...
630 views

### Combining 3 graphics of different coordinate systems

I have 3 graphics in different coordinate systems and I want to join them in as in the following figure. This is just a sample figure, not the real one. My functions are as follows. ...
224 views

I have been trying to solve this problem, it worked slow. I know there is a efficiently way. How do I get it? The following is my code: ...
142 views

### Changing the number of locators with SetterBar

Typically when adding locators I would use a button i.e. something along the lines ...
215 views

### Filling for ListPolarPlot

I want to use Filling for ListPolarPlot in such a way that the points in the list are joined to the origin with a line colored ...
222 views

### While-Loop Linear Projection

I'm would like to do a linear progression for a recursive relation of a consumption function. Combining my program skills and my sparse knowledge of mathematica, I was thinking about doing it in a ...
865 views

### Best Practice to write ::usage for own package functions

I'm writing an own package with Mathematica, that I would like to make available for others. In order to do that (and for my own usage of the package), I would like to write ...
236 views

### Open and search Documentation-Center

In notebooks you can press F1 (or Shift+F1 for a new window) to: open the help page of the marked Symbol or the Symbol under ...
455 views

### Simulating Theatre puzzle

I have been trying to simulate the process of the theatre puzzle from the Joy of X (Strogatz). The puzzle, and some relevant material are here. My simplistic coding for this process follows: ...
117 views

### Non solutions returned by NSolve. And why does it return both phi and Cos[phi]?

Similarly to this thread NSolve gives additional solutions that don't satisfy the equations! NSolve returns "spurious" solutions, even increasing the working precision ...
612 views

### How do I obtain an intersection of two or more list of lists conditioned on the first element of each sub-list?

Given two lists like list1 = {{1, 1}, {2, 4}, {3, 9}, {4, 16}}; list2 = {{2, 6}, {3, 9}, {4, 12}, {5, 15}}; I would like to produce an output like ...
2k views

### Are Mathematica 9 units really slow?

This generates 75 unitized pairs for a plot that displays physical units: ...
291 views

### FindRoot - Speed and errors

I am using FindRoot[] to solve a complicated equation. It seems I get the correct answer even though I get errors about an ...
3k views

### Find all roots of an interpolating function (solution to a differential equation)

I'm trying to find all the roots of the solution to a differential equation. Using NSolve or Reduce I don't get the roots, so I'm using an iterative method which I found in physicsforums.com. This ...
322 views

### How to partition a list and leave in the last sublist which is of different length? [duplicate]

How to partition a list and leave in the last sublist which is of different length? In[75]:= Partition[{1,2,3,4,5},2] Out[75]= {{1,2},{3,4}} I want it to be ...
224 views

### Filter list with different list in it

I have a list like: {{{4, 14}, 1}, {{4, 15}, 1}, {{4, 16}, 1}, {{4, 17}, 1}, {{4, 18}, 1}, {{4, 14}, 3}, {4,15}, {{4, 16}, 2},{4,18}} Now I want to ...
755 views

### Solving Integrals

Here's a problem that I don't understand. f[x_] := Exp[Cos[3*x]] g[x_] := (1/3)*x^3 - x^2 + 2 When I try to find the limit: ...
1k views

### RegionPlot3D in cylindrical or spherical coordinates?

RegionPlot3D is awesome. Unfortunately, it appears to work only for Cartesian coordinates. While there are ways to draw surfaces in spherical or cylindrical coordinates, I can't find a way to draw ...
2k views

### How can I convert a complex number a+b I to the exponent form A Exp(I phi)?

When I have an expression such as: (1/4 + I/4) ((1 - 2 I) x + Sqrt[3] y) it is hard to get an intuition of the number. So I want to convert it to the complex ...
3k views

### How to draw a great circle on a sphere?

I apologize for the text description, but new users are not allowed to post images. I want to draw a circle that cuts through the center of a sphere and has an inclination of 15 degrees with the ...
98 views

### Different behaviour of ValueQ inside and outside of a loop

I need to store a rather big number of variables and I tried to do that by storing each variable as Z[n] with varying n. I guess this was not my best idea. The first problem I encountered is when I ...
545 views

I have a data file with triplets. The first two numbers indicate the x and y position, while the third one is the log10 value of a particular indicator. I want to create a 2D plot in which the ...
1k views

### How to prepare data for ListVectorPlot[]?

I was trying to plot a few velocity vectors measured at given points. However I am unable to do this with ListVectorPlot[] function. I get error each time I try to ...
506 views

### user defined functions, how to save them for future use?

I need certain user defined functions over and over. I was wondering how can I define and where and how to save them such that each time I start a notebook, these functions are available and need not ...
127 views

### How to make a pattern to change x^(2/y) to (x^2)^(1/y) for any x and y?

This might have been asked before. Please let me know if it is. I was looking at an interesting Mathematica question in students forum and trying to solve it, and a chance to learn more about ...
1k views

### Loops and subroutines [duplicate]

Possible Duplicate: Alternatives to procedural loops and iterating over lists in Mathematica I am new to Mathematica and not familiar with functional programming. In particular, I have no ...
361 views

### Tailoring RegionPlot3D with PlotPoints?

This seemingly tame solid gives Mathematica (v9) a bit of a workout if you want to generate a good picture: ...
943 views

### Sales forecast using SARIMAProcess and time-series data

I would like to ask for help in how to use the new Mathematica 9 time series functions to make some sales forecast. For example, for one of our stores, I have this data set with 35 points, from ...
98 views

### Why cant Mathematica solve this equation? [duplicate]

Possible Duplicate: Can Reduce *really* not solve for x here? Why cant Mathematica solve this equation? ...
860 views

### How to generate a picture like this?

How to generate a picture like this? I'd like the surface of the manifold to randomly distort.
444 views

### How to extract Solve results as variables [duplicate]

Possible Duplicate: Assign the results from a Solve to variable(s) In the following example: ...
2k views

### how to differentiate formally?

I have been wrapping my head around this for a while now and I have not found a solution so far. I want to work with an arbitrary number of variables in mathematica and use some built in functions. ...
224 views

### Iterative Function Mapping [duplicate]

Possible Duplicate: How to nest my own “times” function to get powers What I want to do is something like : Sin[...Sin[Sin[Sin[Sin[x]]]]] Basically, ...
109 views

### Draw from HistogramDistribution with ParallelTable

I wanted to check something, but ran into troubles using HistogramDistribution in combination with ParallelTable. The code does the following: Compute a HistogramDistribution of some sample and use ...
301 views

### Making the TableForm output into two columns

I have a program that calculates Christoffel symbols for a given metric, and the output I'm getting now is such that I have every calculated symbol in one column like this: I'd like that I could ...
168 views

### Subscript and Part: What's going on in this example?

Example I came across the following simple example from A Beginner's Guide to Mathematica, by McMahon and Topa, which I believe was written circa version 5.2. (FWIW, I'm using v9.) ...
2k views

### Remove annoying Conjugate

Here is an expression ...
69 views

### Extracting box coordinates [duplicate]

Possible Duplicate: Dimensions of the results of Text[] within Graphics[] In writing the following code, I had to figure out what values to give d by trial and error. Is there a way to ...
573 views

### How can I express an algebraic expression as a product?

I have a simply expression that I can see that I can express as a product. ...
214 views

### Symbolic calculation

Is there any software where this kind of symbolic calculation is possible? s = 0 for i = 1 to m j = 2 i + a - t if (j > 0) s = s + a I want s as a ...
251 views

### Evaluating a function on permutations of its arguments

Say I have a function "temp" of $n+1$ variables, $y,z1,z2,z3,...,zn$. I want to test if my function has certain symmetries like swapping $y$ with square of any $z$, swapping any two of the zs, ...

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