# All Questions

85 views

### Changing default behavior of Series to give slightly different SeriesData

I am working with complicated expressions expr that contains the symbolic function f[x] which I know to have a pole at ...
15 views

### NDSolve printing error message NDSolve::ndode

Using NDSolve while solving system of ODE's. Here is my try ...
61 views

### Simplifying square root expressions

I have read lots of questions on square root simplification on MMA, but I haven't really seen my problem posted (or understood a clear way to deal with this issue). I am simplifying some expressions ...
381 views

### Finding time-series direction reversal of certain magnitude

I'd like to find the points of a time-series that are a certain distance away (in value, not in time) from the previous maximum, which I consider a reversal. For example, for ...
77 views

### How can I get a list of the positions of the running minima in a list?

I want the positions of the (sequential) running minima in a list, that is, the positions of entries that have the minimum value of all the elements in that list, up to and including that entry. For ...
22 views

### How to use pattern matching for integral identities?

I have an unknown pdf f[x], and I need to express integrals involving f[x] as expansions of the moments of f[x]. For example: ...
61 views

### Inconsistent behavior of undocumented Encode->Import->StringToStream->Get on password-locked stream

Let's save a definition. Encode it with password/key and Get it again. We will not use Get ...
45 views

### Adding Assumptions changes the result of Integrate

When I try to calculate the following integral: ...
23 views

### Elements inside arrays seem to be strings rather than signed numbers

When I have code like b = Array[Subscript[be, #] &, {3, 1}] b = b /. {Subscript[be, k_] :> Subscript[-be, k] /; k > 1} I am noticing that Mathematica ...
33 views

### Diagonal minors of matrix

I need to calculate the minor of a matrix. I am going to use Mathematica example here, In[1]:= (mat = Table[i^2 + i j + j^3, {i, 4}, {j, 4}]) // MatrixForm; Minors[mat, 3, Identity] // MatrixForm; ...
74 views

### How to find and verify relationships between functions?

MMa gave me a complicated result involving Hypergeometric0F1's. It was much less complicated after I discovered this identity: ...
34 views

### How to define a function [on hold]

How can I define a function which depends on a function of x? Something like this f[u[x]_,u[x]']= u[x]' + a [x] u[x] +b[x] I think I wasn't enaugh clear. If I ...
22 views

### Deleting rows and columns to get submatrices? [duplicate]

I did not think that this would be difficult to find but how do I drop rows and columns from a full matrix? For example, I would like to delete the last row and first column but have trouble making ...
22 views

### Solving linear recursions without constant depth in mathematica

Mathematica does not like this recurrence relation. I do not understand why? ...
111 views

### Iterating over a list, in a functional way

I have learned a lot about functional programming just from messing around in Mathematica, but I've come across a problem that I don't know how to solve in a "functional" way. Any help would be ...
1k views

### Combining Cos[ ] terms

A function that is the sum of two Cosine terms of the same frequency x[t_] := a1 Cos[w0 t + b1] + a2 Cos[w0 t + b2]; can be simplified to a single ...
79 views

13 views

### How to converrt RGB to YCbCr [duplicate]

While converting rgb to Ycbcr, do we get values as floating point numbers? I would like to have Y, Cb, Cr values as integers. Is it possible?
105 views

### Replace elements in matrix to make it symmetric using automated procedure

I am generating a matrix using (mat2 = Array[Subscript[a, ##] &, {4, 4}]) // MatrixForm but would like to force Mathematica to make it symmetric. Thereby I ...
28 views

### Mathematica refuses to evaluate this expression symbolically while a very similar one works [duplicate]

Suppose I have the following code ...
104 views

### Is Mathematica's (v10.0.2) NetCDF exporter broken?

I'm trying something very simple, namely: Export["file.nc", {"Datasets" -> {"seqs" -> {"AAA", "BBB"}}}, "Rules"] And getting Java errors about "illegal ...
76 views

### Adding Trace produces error messages

This is very strange. As I was trying to debug this problem, I noticed when I add Trace then I get lots of internal errors generated. This also happens the first ...
57 views

### Issues with Arrow and Graphics3D [on hold]

I'm trying to plot a simple picture: a plane with a circle in it, and three vectors in the curve. Mathematica keeps saying that the array "has the wrong dimensions for a graphics coordinate list" and ...
66 views

Just bought a copy of E. J. Mcinnerney's textbook Computational Explorations in Magnetron Sputtering. However, when I download and try Chap2.nb from: ...
40 views

### How can I round a number up with two decimals? [on hold]

My problem is, that I have to round a number with many decimals to a number with two decimals. For example: The number is 3.467. Now I want to get 3.46. I tried it with Round[3.4647,0.01], but I only ...
136 views

### Replacing powers of $n$-th partial sums in the output of a function with $S[i]$ for $i = 1,\ldots,n$

I've written some simple code that, for various $N \geq 1$ and $k = 1,\ldots,N+1$ computes the $n$-th derivative of $\log S_N$ where $S_N(z) = \sum_{k=0}^N \frac{1}{k!}z^k$ as follows: ...
44 views

### Nothing showing up on complex contour plot [on hold]

I am trying to graph the following function, where z:=x+y*I z(Conjugate[z]+2)=3. But with my code nothing is showing up. I've tried many different scales so something must be wrong with the actual ...
68 views

### Plotting Complex Numbers - Functions of Complex Numbers [duplicate]

So I have to generate a few different plots with z, where z is a complete number... z[x_, y_] := x + y*I F[z_] := (25*Pi*z*I)/(1 + 10*Pi*z*I) First, I need to ...
174 views

### How can a function know in which function it was evaluated?

Hello my second question here might be very hard. I am asking for something "magical", if i define a function g and i call it inside a function f, how can g have information about the outer function ...
112 views

### Trying to get Arg[1 + I a] -> ArcTan[a]

Can Mathematica evaluate Arg[1+ I a] when a is a positive real in order to get ArcTan[a]? ...
52 views

### Problem with Simplify, Sqrt, and Set: What's going on?

I am having some trouble getting Mathematica to simplify an expression of the form Sqrt[x]*Sqrt[1/x], where x>0. The problem is that x is assigned to some complicated form by the time Mathematica ...
165 views

### Function to calculate average of multiple lists

I have several lists of experimental data f[x] with different intervals Δx including some noise. ...
45 views

### Unintended effect of closing square bracket on Spanish keyboard in Mathematica online

I have only just started using Mathematica Online and I have encountered a problem already with the ubiquitous closing square bracket ] using a Spanish key board. I ...
94 views

### Random geometrical graph generation

I would like to generate a random graph on $[0,1]^2$. Each node is connected to one other if the distance between two nodes is say 1/4 or less. Here is an example with 50 nodes and 200 edges I would ...
86 views

### How to find soccer balls in an image? [on hold]

I have 10k images and I need automatically remove only soccer balls, excluding other types (volleyballs, baseballs, etc...). I'd like to use computer vision methods of V10 to find their masks and ...
38 views

23 views

### WSMModelData[] can not find my model

I have something like this in my notebook (SystemModeler is not running): ...
50 views

FrontEndExecute[FrontEndToken["EvaluatorAbort"]] is equivalent of the menu item: Evaluation >> Abort. It works with ...