Questions about the use of built-in Mathematica functions, including pure functions.

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2
votes
3answers
260 views

Tracking iterations of a function

I'm learning MMA with Wagner's book. On page 41, he uses this to display the iterative steps of a FindRoot. However, I can't seem to replicate this (code at end), perhaps due to the difference in MMA ...
6
votes
1answer
268 views
0
votes
3answers
88 views

Create polynomials from Series

This question actually doesn't have quite a lot to do with the Series function, but I don't know how to describe my problem. So here's the thing. I'm trying to ...
0
votes
1answer
60 views

Integrating function can't be epressed? [closed]

Hi I have a function in a form of $$\frac{a}{x}exp(\frac{b}{\sqrt{3}-x})$$ The code is Integrate[a/x*E^(b/(3^0.5 - x)), {x, 1, 3^0.5}] But it can't work ...
9
votes
3answers
2k views

How can I differentiate Numerically?

Mathematica has two ways to integrate: Integrate and NIntegrate. But what about D? ...
2
votes
1answer
102 views

Define function that counts recursive fibonacci

If I write count=0; fib[0]:=(count=count+1; 0); fib[1]:=(count=count+1; 1); fib[n_] := (count = count+1; fib[n-2] + fib[n-1]); Then I can ...
2
votes
4answers
343 views

How to completely delete the head of a function expression

Is there any way to completely remove the head of an expression function? For example, how would I remove the head Cos from ...
1
vote
0answers
72 views

Expression for evaluating multiple functions?

I am constructing 3D data points for a plot and corresponding to specific conditions "manually". I define the values of five parameters [these I always have to define myself]. From those, I evaluate ...
4
votes
3answers
204 views

Counting number of inversions

Is there an inbuilt method to find the number of inversions in a set of numbers? I found Inversions in Combinatorica but when I ...
0
votes
1answer
46 views

Switching the ordinate and abscissa causes problem in `ParametricPlot`

I have a function that plots properly in PolarPlot, but I'd like to plot it in ParametricPlot and then switch the y and x ...
0
votes
1answer
95 views

Getting “Null” output from package?

I have a script written to test a package as follows: ...
0
votes
1answer
73 views

Is there a way to make the MemberQ function apply to a list?

Is there any way to ask a boolean question if the elements of the list {2,5} are in the list {1,2,3,4,5}?
0
votes
1answer
62 views

How I can define a new function as a function argument?

I need to pass a function with t as independent variable as a function parameter and want to create a new function of the same through this provided the argument of another function. Here is my code. ...
2
votes
3answers
306 views

find connectivity

Imagine a chain of 20 rings, labeled by 1-20 sequentially. We want to make random size sets of numbers randomly chosen from these 1-20 rings. No duplicate numbers are allowed. Example of a set: ...
0
votes
2answers
201 views

How to pass a list as function argument?

I have the following function lFreqPhylo[a_, Q_, b_, p_] := Sum[Log[freqFunction[r[[p]][[i]], L[[p]][[i]], a, Q, b, {i, 1, nbranches[[p]]}]; The objects L, r ...
1
vote
0answers
56 views

How to find matrix exponential using RootSum?

From what I've been able to deduce, Mathematica uses a root sum scheme to determine the exponential of a matrix. Can someone please explain to me the theory behind this? I've searched, but have had no ...
2
votes
2answers
180 views

Restarting an Animate animation after variable in Manipulate changes

I've been trying to restart an animation after variables change from Manipulate PopUpMenus. My animation takes the form: ...
6
votes
0answers
145 views

Finding hidden treasure (aka finding undocumented functions) [duplicate]

I was searching for a way to determine if a point is within a polygon and stumbled upon rm -rf's answer. (actually, I really wanted to find a point within a ...
0
votes
1answer
69 views

Apply function to output of previous function

I am trying to write a function that takes 3 tuples. Each tuple contains two lists which are first divided. This results in 3 lists. Then I want to take the Mean of all the columns. I can do this ...
2
votes
1answer
75 views

Can Do-Loops iterate backward? [closed]

If I create a Do statement, Do[expr, {i, imin, imax}] is there a way to make the statement evaluate from ...
0
votes
1answer
52 views

ToExpression and Fortran notation

ToExpression["9.0E-03"] interprets String as 9*e - 3 instead of what I am expecting ...
2
votes
1answer
107 views

What is the formula Mathematica uses for ZetaZero?

What is the formula/algorithm Mathematica uses for the ZetaZero command?
0
votes
1answer
135 views

Discrete peaks to curve via Voigt summation

I have two data sets. One is an experimental recording of an absorption spectrum, composed of regularly spaced (wavenumber, intensity) coordinates with a fine wavenumber resolution, thus making ...
2
votes
2answers
87 views

Graphical solution of a a two-variable system containing an equation and an inequality

I'm currently studying atmospheric-gravity waves and their dispersion relations. I want to have look at values of $(x,y)$ that solve the following system : \begin{equation}\label{}(1) \left\{ ...
0
votes
1answer
53 views

Inverse functions - how are they calculated?

Mathematica is able to calculate InverseFunction[LogIntegral] and InverseFunction[RiemannR] (and many other inverse functions). ...
1
vote
1answer
52 views

VertexSize with GraphPlot [closed]

I'm constructing a graph using GraphPlot and I want some vertices to have a different size than others, like this: ...
1
vote
0answers
69 views

Find eigenvalues without filling the matrix

Is it possible to find eigenvalues of a matrix without filling it? The matrix elements are given by a known function f[p1,p2]. This is relevant for a matrix too ...
1
vote
1answer
56 views

Get subgraphs: communities of graph g

I have a graph g. I want a set of graphs c which holds the community subgraphs of g. I ...
3
votes
0answers
78 views

Why does Part behave like it transposes lists? [closed]

From the documentation of Part: Part[expr,i,j,...] is equivalent to expr[[i]][[j]]... ...
2
votes
1answer
78 views

Why evaluation doesn't fail if arguments are invalid? [duplicate]

Sorry for a noob question, but this is something that I wonder about each time I work with Mathematica. Coming from standard programming languages (Python and Java), I expect my functions to fail ...
1
vote
1answer
77 views

How to study the sign of an expression including a function, with conditions on the function?

I'm trying to study the sign of an expression, having information on some of my parameters. I don't know how to code these conditions. For example, I want to know when this expression: ...
0
votes
1answer
64 views

function of derivative of a function

I know a similar question is answered somewhere, but it doesn't work for my case for some reason. I have the following problem in Mathematica. I want to compute f[h[x]]= x^2 + D[h[x],x]. Here, h[x] ...
1
vote
1answer
76 views

Sort lists of vertices {indegrees, outdegrees} by indegree

in = VertexInDegree[F]; out = VertexOutDegree[F]; I want both in and out to be ordered by in. Example: graph has nodes a,b,c with indegrees 1,2,0 and outdegrees ...
0
votes
1answer
42 views

Defining arbitrary order derivatives function [duplicate]

I have a function $\phi(t)$ and I want to define a function $\phi D(t,r):=\phi^{(r)}(t)$, in other words evaluate the $r$'th derivative of $\phi$ at $t$. The naive code that I have is: ...
1
vote
1answer
47 views

Replicability of RandomVariate within a function?

I have a rather basic question but can't figure out a foolproof answer. In the following code, I build a function which returns the mean difference between successive elements of a vector created from ...
0
votes
0answers
30 views

Table of values for functions with random variables [duplicate]

I'm trying to get a table of values for functions with random variables. First of all, i have a function like that: ...
0
votes
1answer
75 views

Problems with For statement

I'm trying to iterate some expression through for loop: ...
0
votes
0answers
68 views

Financial Derivative european call option

When estimating financial derivatives like a european call option there is a parameter named: dividend paid per time unit. What does this mean, I have not been able to find any more information about ...
0
votes
1answer
94 views

Mapping a function over n levels

I want to map a function over a matrix of rank n, for example: ...
1
vote
3answers
149 views

Testing for continuity over a given domain

Is there any way to use Mathematica to test whether a function is continuous over a given domain?
0
votes
0answers
106 views

Solve function doesn't work

I have the following system of equations that I need to solve: ...
2
votes
0answers
97 views

A math function similar to “LatticeReduce” for finding linear independent basis

We would like to ask a math function similar to "LatticeReduce" for finding linear independent basis. The input is a list of vectors $M=\{v_1,v_2,v_3,\dots\}$, with the following property: There is a ...
1
vote
1answer
58 views

Compose two special power series expansions

I have two functions $A(x), B(x)$, given in a special power series form: $A(x)=1-x^{2}\left(\frac{a}{10}-\sum_{k=1}^{9}b_{k}\left(\frac{(x^{2}-1)}{r}\right)^{k}\right)$ ...
4
votes
4answers
209 views

Speed up replace all

I have large list of rules, I would like to use list/.rule, but assume that rule is a set of rules rule 1, rule2 rule...I want ...
1
vote
1answer
116 views

Time Varying Payoffs?

I'm trying to write some code that will return the final value of an annuity whose monthly payouts may or may not be constant each month. Right now I have working code for constant payments, but I'm ...
1
vote
1answer
184 views

ListDensityPlot

In Mathematica help it's written that: ListDensityPlot[array] -> generates a smooth density plot from an array of values. ...
6
votes
1answer
112 views

Is it possible to circumvent a bug inside SeriesCoefficient?

As far as I can tell, there seems to be a bug in SeriesCoefficient: ...
1
vote
1answer
114 views

How to define a list that contains all primes less than x?

how can I define my own list in which I have all primes less than x?
0
votes
3answers
78 views

Half kth term if n is even and k=n/2?

I am trying to write a function which will perform the equation in the attached image. So far, I have: ...