1
vote
3answers
223 views

plotting an Integration output

How to solve this integral by Mathematica even by numerical methods (plotting the solution) Integrate[(Cos[x] - a)/(1 + a^2 - 2*a*Cos[x])^1.5, {x, 0, 2*Pi}] It ...
1
vote
2answers
92 views

Missing something in my input for CountryData dependencies

I'm trying to find (a)which countries have dependencies (b)and a list of countries that consider themselves dependencies (c)and a list of countries that don't consider themselves dependencies. ...
-1
votes
1answer
435 views

Gamma Incomplete Function representation in Mathematica and Matlab

I am confused about incomplete gamma function calculation in Mathematica and MATLAB: For example, in Mathematica: Gamma[5,3] = 19.56 But in MATLAB: ...
8
votes
2answers
281 views

Problem importing a JCAMP-DX mass spectral file

I have some problems importing a JCAMP-DX EI-mass spectral file using Mathematica 9. For example, if I download the mass spectrum of nonacosane in JCAMP format from NIST, ...
0
votes
1answer
134 views

Manipulating and using result of DSolve

I have an unsightly looking equation that nonetheless has an analytical solution. The solution is ugly as hell, but exists; I use the following code with the DSolve ...
4
votes
2answers
918 views

ArcTan[z] and ArcTan[x,y], Restriction and Conversion

In Mathematica there are two different forms for the arctangent (inverse tangent), namely ArcTan[x,y] which gives the arc tangent of $y/x$, taking into account ...
2
votes
1answer
246 views

Why is this expression being held, and how can I evaluate it?

I can't figure out why an expression isn't evaluating, even though there's no Hold* in its FullForm: ...
2
votes
4answers
212 views

Where did I go wrong with my implementation of finding a plane tangent to a surface?

I am working on finding the plane tangent to a paraboloid at a given point. My code: ...
1
vote
1answer
164 views

DSolve expression not evaluating

I entered the following into Mathematica: p[x_] := 4 x q[x_] := 4 Sqrt[x] - 3 f[x_] := E^-Sqrt[x] DSolve[y''[x] + p[x] y'[x] + q[x] y[x] == f[x], y[x], x] ...
3
votes
1answer
205 views

When does the real part of Zeta vanish on the critical line?

This seems to be a quite a simple problem but I cannot make it work. I am trying to find all values within a given range for which the real part of the Zeta function vanishes on the line: ...
1
vote
1answer
367 views

How to effectively compare two sentences and say both are equal

want to compare two text file. Suppose file AA contains following text ...
6
votes
1answer
283 views

Efficiently searching a list for the position of the closest number to a specified number

Searching by closest and position I wasn't able to find an answer—but found Nearest by guessing. Nearest, however, returns ...
1
vote
3answers
151 views

automatic processing of numerical results in `Plot`

First I want to solve an equation $F(x,y)=0$ for $y$ by supplying a value of $x$. (suppose obtaining the analytic form of $y(x)$ is too difficult) Then I want to plot root $y$ (numerically calculated) ...
1
vote
1answer
151 views

Plot3D missing a zone

I am trying to plot a simple graph using Plot3D: ...
3
votes
2answers
340 views

Assigning an analytical approximation to the error function erf(x)

Working with some iterative integral equations, I have Gaussian density functions involved therein. Integrating the Gaussian function I obtain the error function. When I take the second integration, ...
0
votes
1answer
104 views

Function generating a rule with a Patterns: e.g. toRule[ lhs, rhs] into lhs[x_] -> rhs [duplicate]

I want to create a rule as a function of z from a left and right hand side. My (non-working) code and usage is: ...
0
votes
2answers
87 views

Display Part Of or Summarize Other Notebooks

How might I display parts of(or basically summarizing) one Notebook from parts of several other Notebooks? This isn't a strict question question but more of a general/wiki question of how to organize ...
3
votes
3answers
331 views

How Can I superpose an image and a graphics?

I want to superpose an image with a graphics in order to evaluate their alignment. I am writting this exemple of code. ...
1
vote
1answer
650 views

Is LinearSolve the most robust way to solve the equation $Ax=b$?

I want to solve the equation $Ax=b$, where $A$ is an $n\times n$ matrix, and $x$ and $b$ are $n\times 1$ column vectors. Here $n=124$. LinearSolve[A,b] I got the ...
0
votes
2answers
285 views

using index notation for finite differences

I am interested in deriving finite difference equations, which means I have to play around with indexed quantities. For example, for a 2D function f(x,y), I could discretize it on a grid with grid ...
1
vote
1answer
137 views

Problems with formatting a bar chart

I am trying to create a financial dashboard using Mathematica. I am having trouble formatting the axes ticks to show whole numbers. Further, when I hover over one of the chart elements, it is ...
1
vote
1answer
234 views

No Speedup Compiled Function in FindMinimum

The problem: I would like to minimize an objective function with respect to 12 variables. Minimization should be executed as fast as possible. Compiling the objective function increases the execution ...
5
votes
0answers
136 views

Texture[] not working properly with Image AlphaChannel

I recently encountered a problem when combining multiple texture layers in an graphics object when the texture comes from an image with alpha channel. Apparently the alpha channel of the image passed ...
1
vote
0answers
33 views

Pattern matching list elements in pure functions [duplicate]

Pattern matching here is a functional programming term, but it might be called differently in Mathematica, I'm not sure. It is possible to match the elements of the list in a regular function ...
0
votes
1answer
192 views

Plot lines keep disappearing

I'm trying to plot the Compton Shift which I've defined as: E2[ϕ_] := E1/(1 + (E1/(m*c^2))*(1 - Cos[ϕ Degree])) I've initiated the constants and when I evaluate ...
4
votes
4answers
265 views

How to compute MIN$(A(x), B(x))$

I have two polynomials: $\;A(x) = \sum a_i\;x^i$, $\quad B(x) = \sum b_i\;x^i$. Given $A(x)$, $B(x)$, I want to compute $\;C(x) = $MIN$(A(x), B(x)) = c_i\;x^i$ where $c_i = $MIN$(a_i, b_i)$. How can ...
7
votes
1answer
470 views
0
votes
0answers
176 views

Connection between Mathematica Connector/J and XAMPP MySQL Database

I have been fiddling around with a problem for a while now, and hope you can help me. Have searched for previous solutions, but nothing seems to work. My problem is as follows: I have XAMPP ...
8
votes
5answers
296 views

Refer to next element of list when iterating using Map [duplicate]

Is it possible to refer to the next element of the list when I'm using Map or should I always use For in this case? For example ...
1
vote
1answer
434 views

FindMinimum [] methods

Which algorithm is used when we do not use the option Method of FindMinimum[] function. FindMinimum[f,{x,x0}]
1
vote
0answers
104 views
12
votes
1answer
322 views

Is everything in Mathematica ultimately stored as a rule?

My current understanding about Mathematica is that everything, at the lowest level, ends up as replacement rules. First question: is this true? Second question: does Mathematica "gloss over" these ...
1
vote
1answer
133 views

What's wrong with my palindrome finding function?

I'm trying to find the palindromes in the dictionary, but my output isn't giving me all of them. I have this so far ...
0
votes
0answers
25 views

DialogInput inside ButtonBar freezes Mathematica [duplicate]

In Mathematica 8, if I press a button on a ButtonBar which contains a DialogInput Mathematica freezes. Is this reproducible and ...
2
votes
1answer
549 views

Differential equations: Solving a singular/nonlinear ODE using NDSolve

I am trying to numerically solve a rather horrible looking singular/nonlinear ode: A*(y''[x]/y[x])'' +y[x]^2==1 on the interval ...
0
votes
0answers
103 views

calling a batch or executable application on Windows

How to run a batch file, send commands and collects output on windows Run["!C:\\runme.bat"] it outputs 1 and a window appears and then disappears. I also want ...
0
votes
1answer
226 views

Customizing AxesStyle->Arrowheads

How do I call AxesStyle->Arrowheads[ ] in order to control whether or not an arrow appears on each of the four ends of the axes in a ...
2
votes
1answer
86 views

File output and race conditions

Is it possible to know when Mathematica is done writing a file? I'm looking to automate something and I'm wanting to have Mathematica put it in a file using Put[], ...
2
votes
2answers
195 views

How to replace data in a list (tree) in a functional Mathematica way?

I have list containing 2D points in various groupings, i.e. points, lists of points (figures), lists of lists of points (patterns) and finally a list of patterns. The list also contains other data, ...
0
votes
1answer
330 views

Convert expression to C-form and simplifying

I have an expression which is the sum of many terms of the form $$ \frac{0.00000000274341}{(0.000363856+(0.611425+z)^2)^{3/2}} $$ My problem is that I need to include this long expression in a ...
6
votes
1answer
174 views

Random filling of L-length line with l-length segments

I have discrete L-length line filled randomly with 2-length segments so its cover line with gaps 0 or 1. So we can describe cover configuration as sequence of gaps such as {0,0,1,0,1}. How I can ...
5
votes
2answers
155 views

Strange Behavior when making Equal Listable in Pick

While trying to make this problem more efficient I tried different methods and dabbled with making Greater and Equal ...
4
votes
3answers
701 views

How to increase Spectrogram resolution?

I have a time-domain signal that I want do a time-frequency analysis on it. When I tried the Spectrogram, I always get very low resolution. For example: I have a ...
2
votes
1answer
317 views

How to use NIntegrate in a purely numerical mode?

I have a function that is defined as the smallest root of a given polynomial. Something like this: ...
4
votes
2answers
215 views

J/Link: How to run a thread inside Mathematica

In the J/Link User Guide there is no example on how to use java.lang.Thread, from inside Mathematica. I'd like to know if is possible to start a thread from a ...
6
votes
1answer
95 views

Why only up to two \[Prime] superscripts are interpreted as derivatives?

I noticed that only up to two \[Prime] superscripts are interpreted as derivatives. Is there a reason for this restriction? Is it documented? ...
3
votes
1answer
168 views

Adding and summing overlapping Airy (or Gaussian) disks on a plane

In a previous question of mine, I asked how one might draw an Airy disk on a plane: Generating an Airy disk on a plane, and recieved some impressive answers from the users Timothy Wofford and ...
3
votes
0answers
128 views

What is the signature for a callback function for FinancialIndicators?

I'd like to write my own indicators to use with functions like TradingChart. From the context, it's clear that one needs to write a function whose parameters ...
2
votes
1answer
162 views

Copying each object in a plot separately as an image

I would like to copy a plot from Mathematica as an image, into a PowerPoint slide. This plot has two curves. When I try to do the (naïve) usual "copy graphics" and paste, I find the full plot (along ...
0
votes
2answers
142 views

Put results in multiple columns for comparison

One thing I would like to do in many instances is arrange input/output in columns for comparison. I expect that I need to use Grid to do this, but have not been ...

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