# All Questions

1answer
23 views

### Plotting separatrices for nonlinear system

Consider the system: \begin{align*} x'&=(1-x-y)x\\ y'&=(4-7x-3y)y \end{align*} The system has a saddle point at (1/4,3/4). How can I plot the separatrices on the phase portrait having domain ...
0answers
16 views

### Make animation with multiple external data files

I am currently solving PDEs for a discrete vector field with C++. The output at a time t is an array where each row represents a site and there are 6 columns, the first 3 give the position of the site ...
1answer
32 views

### Iterating distributions

I want to calculate the distribution that comes from summing up random numbers between -0.5 and 0.5. A computationally intensive version of doing this is to simply do the following: ...
0answers
21 views

### Differing results with Map and ParallelMap

I am using Mathematica 10.0.2 and I am trying to change the string Class_1 to 1, so I use the following code: ...
1answer
36 views

### Why this error?

f[x_] := Piecewise[{{1, -0.5 <= x <= 0.5}}, 0]; ProbabilityDistribution[ Integrate[f[a], {a, x - 0.5, x + 0.5}], {x, -2, 2}] output: "Unable to prove that ...
1answer
21 views

### Kernel quits without error in NDSolveValue

I am using the latest 10.1. The following single line command makes the kernel quit without error message (just a beep): ...
0answers
38 views

### First Order Conditions

I am new to Mathematica so I am not sure if this is correct. I have setup up a Lagrangian and I am trying to get the FOCs of this problem. However, it does not seem to work. Any help would be much ...
0answers
29 views

### Find first n roots of a function

Is there a straightforward way to find the first $n$ roots of a function? I have found various ways of finding roots in an interval, but none that would keep looking for roots until they find a ...
1answer
41 views

### Forcing Exact Outputs for Integrate

I'm trying to compute the following triple integral: ...
0answers
27 views

### MoonPosition and TimeZone support

With this question, I noticed some some weird results of MoonPosition. Consider the following code: ...
0answers
59 views

### Why Mathematica doesn't solve this equation?

I look for solve my geometry problem. To do this, I need get formula for "d" in my equation: ...
1answer
37 views

### Change numerical plot labels on one axis to strings

This question likely has a straightforward answer. Suppose I have a plot something like this: ...
1answer
30 views

### using output in pure function

Suppose i have an integral which has a close form, $\int_{a}^{b} f(x) dx=F(a,b)$ I want to use output function $F$ as a pure function, like F[a,#]& so i try ...
0answers
18 views

### power series or taylor series for transcendental equation [on hold]

Can anyone please show me how to find a power series or taylor series for $p(h)$, an implicit function of $h$ implied by the following equation: $-plog(p) - (1-p)log(\frac{1-p}{n-1}) - h = 0$ ?? ...
1answer
34 views

0answers
37 views

### Can I redefine the ++ increment operator to make it behave like Haskell

In Haskell, joining two lists l1 and l2 is simply done with l1 ++ l2 In Mathematica ...
3answers
170 views

### Calculating average distance between maxima

I'm having trouble figuring out a way to analyze some simple data. When graphed, the data I have make a somewhat sinusoidal curve. What I want to do is to find the x-values of the maximum peaks of the ...
1answer
59 views

### Using Wolfram Library Reference in Excel VBA

Long time ago I did this question to MathGroup, but without success. In Excel VBA, in Tool/References, there is a option called "Wolfram Mathematica Control 8.0 Type Library" I belive that ...
1answer
42 views

### How to combine 2d and 3d plots with this code [duplicate]

I found a picture for example in google and I want to do with my code like that: And here is my code: ...
0answers
21 views

### ListContourPlot for 3D data [on hold]

I have an n x 3 list of some solar cell data that looks like this. ...
1answer
30 views

### Integrating the second derivative of a 3D curve

I have a 3D curve K2[s_] := c1[s] + 0.4*(j[s]*Sin[500*Pi*s/97.8] - v[s]*Cos [500*Pi*s/97.8]) where j and v are frame vectors. I want to find the integral of ...
1answer
101 views

### How to access an already opened Excel file in Mathematica?

This post 4594 shows how to open a existent Excel file with Mathematica. And this 6686886 shows how to do what I need, but in C#. This 12282310 is another related one. How can I connect to a ...
1answer
33 views

### Is there a way to change the indentation behavior of the postfix operator //?

For example, using newlines after // results in some really weird indentation: Ideally, I'd love to be able to do something like this: ...
1answer
82 views

### Finding a formula for a 3D shape and colouring it

I created a wall with line command ...
2answers
87 views

### FindShortestTour to solve Traveling Salesman Problem

I'm trying to write my own code to find the shortest route but I'm lost on how or where to start. Does anyone have any idea how the FindShortestTour function works? What type of algorithm or structure ...
2answers
33 views

### Dataset Query using Composition fails but RightComposition works - why?

V10.1 on Win764 Enterprise. In this (CORRECTED) example the two Queries may be compounded into one using RightComposition sucessfully... ...
0answers
44 views

### Problem with greek!

I am using mathematica v10. I have two promblems. 1. I cannot open notebooks made from another version of mathematica(I open them and i cannot read the greek fonts in a cell which i have wrote) 2. ...
2answers
78 views

### why MeanFilter is nearly 100 times slower than MovingAverage for 1D array?

I used to average over my data with MeanFilter before I learn about MovingAverage and thought that these two functions are similar except that MeanFilter is more powerful for its ability to deal with ...

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