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

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6
votes
2answers
124 views

How to introduce two successive points inside the FixedPointList for each cycle?

If we want to draw the attraction basins of an iteration function of the following type $$x_{k+1}=x_k-\frac{f(x_k)}{\frac{f(x_k)-f(w_k)}{x_k-w_k}},$$ where $w_k=x_k+b f(x_k)$, $b\in R-\{0\}$, we can ...
0
votes
1answer
42 views

Computing approximations of exponential [closed]

I have the code f[x_] := 13 x e^-x bit = Nest[f, 1, #] & /@ Prepend[1]@Range[4, 16, 4] Which I am using to compute values of $f^{(4)}(1), f^{(8)} (1), \...
0
votes
1answer
58 views

Using Plot3D for finding trend clearly

I have a function of two positive variables $t$ and $C$ with $t$ and $C$ in a specific range as below. $0 < C < 10^{-5}$ and $0< t <4.54 \times 10^{-6}$. I want to see which variable of $...
1
vote
1answer
31 views

Iterating my function by $4$ using NestList — Syntax Confusion [duplicate]

I want to iterate my function $f(x) = 13xe^{-x}$ by $4$ multiple times. That is, $f, f^{4}, f^{8}, f^{12},\cdots$. Using Nestlist[f,x,4] I can get $f,f^{(2)}, f^{(3)...
0
votes
2answers
106 views

Trouble creating a bifurcation diagram of a trajectory

I wish to create a bifurcation diagram of the trajectory made by $f(x,a) = a - x^2$ which shows the tangent bifurcation point and the period doubling point. The tangent bifurcation point occurs at $\{...
0
votes
0answers
28 views

Obtain a SymmetricReduction of a bivariate (symmetric) function given in Piecewise form

I would like to re-express the following bivariate (symmetric) function (defined over the unit square) ...
1
vote
0answers
48 views

Creating an indexed set of functions with the indices in the function names [duplicate]

As the titles describes, I want to create a list of functions like the following, where the indices are not in the argument slots: ...
2
votes
1answer
65 views

Create an accumulator array from a function

I am making some images for a project about the hough transform line detection, I am showing the slope-intercept form , the normal form and their accumulator arrays to show the peaks. I am kind of new ...
1
vote
1answer
53 views

Using the Nest function — Confusion on my output

I have the following code and output where the original function is $f(x,a) = a^2 - x^2$. ...
5
votes
1answer
114 views

The implementation of FunctionRange

How exactly does the FunctionRange work? What kind of algorithm does it use? I looked it up in the manual but it doesn't provide any references or even a name of ...
0
votes
0answers
28 views

Symmetric properties of KroneckerDelta under replacement

The consider the following code: ...
2
votes
0answers
53 views

Different behavior of Power between versions 9 and 10

Rather by accident I've noticed that the following trivial code produces different output in Mathematica 9 and 10: -((-1)^n) Mathematica 9: $-(-1)^n$ ...
2
votes
0answers
63 views

How do I define a collections of commands for later use? [duplicate]

Many ask me to tackle this problem by making another function(subroutine) of the lines I want to pick out, using Block,Module,etc The problem is different here.Notice that Block and Module ...
4
votes
0answers
71 views

RealDigits and functional style

So while thinking about Replacing numbers of which you only know certain digits I have faced, again, a problem that I find hard to extract from RealDigits' output ...
1
vote
1answer
47 views

Want to map over both the file data and the file names of the data source files

I have a lot of experimental datafiles I would like to plot first and check, if they can be used for further analysis or not. To avoid importing every single file I used FileNames and than mapping. ...
3
votes
1answer
74 views

plotting after solve does not display anything

I'm quite new to Mathematica language, I am trying to figure out where I am making mistakes in Plotting a specific function that depends to other variables: I want to plot ...
4
votes
5answers
322 views

Alternative to Sign

The Sign function works in a very straightforward manner: Sign[8] Sign[-8] Sign[0] ...
1
vote
2answers
77 views

Problems using a function as an argument

I made a function: f[x_]:=x^2+1 and when i use it on, for example f[5], i get the answer 26. . But when i use it on: PollardRho[a_, f_] := Module[ {}, Return[f[a]] ] And when i write ...
0
votes
1answer
45 views

Using the Solve function [closed]

I am new to using Mathematica and am attempting to find the roots of a function using the Solve[] function. I can replace $f[x]$ within Solve[] with the actual function and it will work that way, but ...
4
votes
1answer
114 views

Associations complement

So I'd like to complement two associations through shared keys... not the best description, so here's an example: ...
2
votes
2answers
154 views

Revolve a non one-to-one function about the y-axis

I am attempting to revolve $f(x)=-x(x-3)(x-2)^2$ about $x=0$. What I have come up with is that I need to redefine each interval between the relative extrema as a separate function, and then treat it ...
3
votes
2answers
105 views

How do I run 1-855 data points( imported from excel sheet) into a formula to obtain value for each data point?

I am very new to Mathematica and I just couldn't figure out the solution for the following problem. I have two columns in an Excel file. I have imported the 1st column as ...
1
vote
1answer
53 views

Define a function interactively with sum

I have to define a function which has 1e4 terms added up together. f(x1, x2) = (sum i, j, k, l from 1 to 10) (C(i) * C(j) * C(k) * C(l) * exp( (alpha(i)+alpha(j)) * x1 + (alpha(k)+alpha(l)) * x2 )...
4
votes
1answer
225 views

Computing the Caputo fractional derivative of a polynomial

In fractional calculus, the Caputo derivative of a monomial has the following form: $$\operatorname{\mathit D}_t^\alpha\,t^\beta = \frac{\Gamma(\beta+1)}{\Gamma(\beta-\alpha+1)}t^{\beta-\alpha}$$ I ...
2
votes
1answer
54 views

Simple plot but the origin is not clear [closed]

I am having problem with the simple plot below. Plot[1/(1-x), {x, 0, 1}] I got the result: As you can see the origin (0,0) is not clear. The value of the function at x = 0 is one but it is not ...
0
votes
1answer
47 views

How is the DistributionFitTest[data, dist] function actually using the dist parameter?

The first "Applications" example given for the DistributionFitTest of the Wolfram Language & System Documentation Center is: Analyze whether a dataset is drawn from a normal distribution: <...
1
vote
1answer
48 views

Having trouble taking derivative of a function and assigning it to a new function [closed]

I am trying to take the derivative of a function and assign it to a different function name, but I am getting an error message (I think). Here is my Mathematica input: ...
6
votes
1answer
149 views

P-values differ in tests for normality between Mathematica and SAS

I am testing the following data for normality, in Mathematica and SAS: ...
11
votes
6answers
446 views

Reshaping associations, generalization of GroupBy

Let's say we have a set a\of associations: ...
12
votes
1answer
892 views

Why is this 2D plot so slow?

I first do a 3D Plot of four surfaces (eigenvalues of a $4\times4$ matrix) over $kx,kz$ (setting $ky=0$ all along). And then I try to give a 2D plot along three connected particular lines in $kx,kz$-...
4
votes
1answer
106 views

Do Any of the filter functions perform a LOESS or LOWESS filter?

From the Data Transforms and Smoothing guide there is a link to the Linear and Nonlinear Filters guide. Do any of these filter functions perform a LOESS or LOWESS filter on set of paired data? ...
1
vote
1answer
85 views

Double arguments and place of the underscore

Could someone explain me of this bit of code below is correct: Is it possible to define a function with a second bracket, see below, i.e. f[x_][y_]? And what does ...
1
vote
1answer
58 views

How to properly plot a unit pulse? [duplicate]

I am using this function to plot ...
19
votes
5answers
498 views

Partitioning a list when the cumulative sum exceeds 1

I have a long list of say 1 million Uniform(0,1) random numbers, such as: dat = {0.71, 0.685, 0.16, 0.82, 0.73, 0.44, 0.89, 0.02, 0.47, 0.65} I want to ...
1
vote
1answer
76 views

How do I write a function inside a ArgMin

I want to solve this ArgMin[NIntegrate[(Tanh[x] - Erf[x/a])^2, {x, -5, 5}], a] and it does not work, what is the correct way to do this? ...
1
vote
2answers
51 views

using Map to apply 2 lists to the LCM function - help [duplicate]

I have 2 lists of numbers and I want to quickly compute the array of answers to the LCM function for the 2 lists and a 3rd static number. I tried the following ...
1
vote
0answers
90 views

Using functions in Solve [closed]

i wanted to calculate the real roots of a function. To my knowledge the function i defined has no real roots, so i expected an emptyset, but instead i got some Root[...#..] answers by Mathematica. ...
0
votes
0answers
52 views

Personal Reminder with Speak capability repeats multiple times

I am trying to create a personal reminder for myself using the Speak function in Mathematica hoping that the computer speaks the task only once at the designated time. However, I have found that the ...
2
votes
1answer
133 views

Find a family of curves

I have a diagram with seven curves (each with a different parameter). My goal is to find a function for the family of curves (i.e. a single function not just for the seven parameters, but for all ...
2
votes
2answers
66 views

Multiple functions with shared arguments in Manipulate

I am trying to define multiple functions with the same set of parameters and then put them in a Manipulate to simulate their behavior. Ideally it should be something like that: ...
0
votes
1answer
50 views

How to apply a user-defined function to a list [closed]

I'm using Wolfram | Alpha Pro; I have a function f[n] = 351n^(-0.7); How do I apply it to each element of a list like {2, 9, 22}? f/@{2, 9, 22} just results in ...
6
votes
2answers
141 views

Getting an explicit representation of the function returned from Interpolation [duplicate]

I am using Interpolation to get an InterpolatingFunction that fits a set of points. For example, ...
5
votes
3answers
183 views

How to tell Mathematica to get the real-only inverse function?

The problem I have is that Mathematica seems to play better with complex numbers so that the result of N[InverseFunction[Function[x,x^3]][-1]] is ...
0
votes
1answer
99 views

Interpolate the discrete list into continuous function

I have a data whose list plot shows up following graph I would like to interpolate the missing data and make the function continuous but for particular x-coordinate there is multiple values of $y$ ...
1
vote
0answers
31 views

Function with many lines that takes image as parameter not returning same result as if I run the same lines of code

Running the exact same lines of code in a function produces just a return of the original image without any points identified, whereas when I run the exact body of the function line by line it works ...
0
votes
2answers
66 views

How to find the value of a variable using solution of Simultaneous equations? [closed]

I have to find the value of p where p=a1*x+b2*y; using the solution of the equation ...
1
vote
0answers
91 views

Need help interpreting a small block of code [closed]

I have recently "inherited" some Mathematica scripts which I need to interpret to write in some other languages (Maple and C++). I have never used Mathematica before so I have been learning on the job....
3
votes
1answer
74 views

Define a function with multiple lines mathematica [closed]

How is this done? ...
1
vote
2answers
70 views

defining a function using other functions

I have the following code: ...
3
votes
1answer
123 views

The basic primitive recursive functions

How can the basic primitive recursive functions be expressed in the Wolfram Language? Apparently here's an example for primitive recursion: ...