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

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0
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0answers
56 views

break down the function

I am using Series function, but I found that it cost too much time. Since the Series function is Taylor expansion and I only need first order, I want to break down the code, so I can make it faster <...
0
votes
1answer
58 views

Why my Function Has no Output Plot?

Below is my commands on a mathematica script to plot a function. In order to see why the function has issue to be plotted, I have tried to plot the intermediate functions one-by-one. It seems that my ...
1
vote
1answer
67 views

How to extract all necessarily code for a function?

Many times when someone pastes a piece of code into SE there are missing values and symbols that the user left out. To prevent this I'm looking for a function that uproots other functions (extract ...
1
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0answers
49 views

Is there any way to see a kernel function's code? [closed]

I was using the extremely useful function PrintDefinitions from the GeneralUtilities package and I encountered this: ...
4
votes
1answer
80 views

How to pass a pair of values to Table function?

I define a function like this: ϕ[t_,ϕ0_,ϕ1_]:=ϕ0+ϕ1/ArcSin[0.97] ArcSin[0.97 Sin[2Pi f(t-0.25/f)]]/.f->30 which generate: $$ \phi (t)=0.754586 \times \...
0
votes
1answer
57 views

Transform a variable's exponent from an exact rational to an inexact decimal

here is a little problem I could not find a solution for. I have a variable with an exponent represented as a fraction, for example, var = a^(39/106) Now I ...
2
votes
2answers
72 views

Why is the square of a differential operator not evaluated automatically?

I defined an operator: py[f_[x, y]] := (I*h*D[f[x, y], y] - x) // Expand (not important, but it represents a simplified component of a quantum momentum in a ...
1
vote
1answer
82 views

Excel lookup function? [duplicate]

I have two lists, one for the length of words and another list for the corresponding bonus points. ...
2
votes
2answers
71 views

Omit argument specification in function [duplicate]

If a function has e.g. 5 input arguments (a,b,c,d,e), how can I omit to specify only argument c, so that its default value is taken, but the other arguments should be passed to the function? E.g: <...
5
votes
4answers
104 views

Using roots to get original equation

I have a list of four rules, that I would like to use to find the original polynomial that produced them. The rules are of the form ...
2
votes
0answers
32 views

Solving for coefficients of a polynomial? [closed]

I'm sure I'm doing something wrong here, but I'm damned if I can figure out what. I'm trying to find a cubic function that passes through (0, 270), (1, 312), (2,230), (3,0), but the first way I tried ...
0
votes
0answers
28 views

A bootstrap on the p-value of a simple linear model

My model: $y_t=\beta_1+\beta_2x_{2t}+\beta_3x_{3t}+u_t$, with $u_t\sim N(0,\sigma^2)$. My sample is of size 50. I'm trying to do a parametric bootstrap for the t-statistic of $\beta_3$, and I'm ...
3
votes
2answers
108 views

Matrix Diagonalization programming

I have a very simple problem, with me misunderstanding the use of Modules and Functions in general, in mathematica. I have a function of which I want to input a Matrix, and in the function I want ...
0
votes
1answer
36 views

WhenEvent StopIntegration not working [closed]

I am trying to use a WhenEvent to StopIntegration when Tmelt=1356 is reached. Although the NDSolve appears to be working, "StopIntegration" is not stopping the integration and no value is given for ...
0
votes
1answer
42 views

Finding text files in a given path and applying a function to those files

I made a function called "SolveLinearSystem[]" that solves,as its name suggests, a linear system of any amount of variables. It takes the path of a text file as its only argument. The function then ...
2
votes
1answer
86 views

Fitting EV charging curve

I would like to fit my set of data (x = time and y = power) as seen below, and obtain function of x describing it as close as possible, in order to manipulate it (applying different SOC, time offsets ...
0
votes
0answers
61 views

Wolfram Mathematica: Sum of a function over a list [duplicate]

I have the function: $I_q(n)=\frac{1}{n}\sum_{d|n}\mu(d)q^{n/d}$, where $\mu(d)$ is the Möbius function. How do I get it in Wolfram Mathematica? It should be something like that: ...
0
votes
0answers
37 views

Names disapper when using PlotLegend [duplicate]

I am using Mathematica 8.0.1.0 and when I use PlotLegend the names disappear. Could you help me fix it? Thank you. ...
1
vote
1answer
54 views

Building function where the output is graphic [closed]

I want to build a function, where the inputs are points and voronoimesh, and points. But, the output would be a graphics parameter. the code is following: ...
2
votes
0answers
74 views

Function output

I would like a function that computes Cartesian product of two sets z=(Tuples@{#1,#2}), and computes the number of elements in this set(list) ...
10
votes
1answer
103 views

Slot number cannot be filled

I got a strange message with the derivative of a two-argument function defined by a definite integral. For example if "f" is defined as: ...
0
votes
2answers
137 views

How to define a formula-less function? [closed]

How can I tell Mathematica that $f(t)$ is a function of time without providing it with a formula? I want to write an auto Lagrangian calculator. And a derivative taker is needed which writes the ...
0
votes
0answers
27 views

Find Sequence Function and Clustering

After I created the eventfinder function (see 1st question First position of incremental series), for increment 20, I found that the incremental Events Manifest at: ...
1
vote
2answers
132 views

How to show convergence to a number?

How can we show that, using either of the two equivalent functions, we converge to some number? $$\sum_{n=0}^\infty f(n)\ =\ 2.75056...$$ $$ f(n):=\frac{1}{\binom{\frac{1}{8} \left(2 (n+2) n+(-1)^{n+...
0
votes
0answers
53 views

Using DeleteCases to ignore term of Product

I'd like to calculate $\int_{-\infty}^{\infty}\mathrm{d}x/(1+x^6)$ through a variation of the residue formula, which is $\int_{-\infty}^{\infty}f(x)\mathrm{d}x=2\pi i\sum \text{Res }f$ for Residues in ...
0
votes
0answers
32 views

Solving for limit of integration with a piecewise function (FindRoot vs NSolve) [duplicate]

I am trying to solve for the limits of integration using a piecewise function. I'm doing this in a loop over a list of data, mostly because I'm not well-versed enough in Mathematica to make this a ...
1
vote
2answers
133 views

How do I get Series[] as a functional, rather than as an expression (i.e. to avoid the dummy variable)?

How can I write an equivalent to Series that doesn't require a dummy variable? Note that the series should be constructed before the evaluation point is supplied, ...
1
vote
1answer
40 views

How do I convert an expression that is a function of some variables into a functional?

If I have an arbitrary f[x, y, z], how do I convert it to f[#1, #2, #3] & without messing up scopes or causing scope leakage?...
1
vote
2answers
133 views

Express roots of quadratic equation in a specific form [closed]

By solving this equation, I got two roots as follows: Solve[1 + Subscript[a, 1]*s + Subscript[a, 2]*s^2 == 0, s] Is there a way to express it in the form below ...
5
votes
2answers
138 views

Using OddQ and EvenQ in piecewise functions: Buggy?

I was trying to evaluate a sum over a piecewise function, not unlike this example. However, my piecewise function needed to be defined differently for even and odd ...
7
votes
1answer
293 views

Branch cuts of sqrt

I was trying to plot some complex functions with branch cuts on mathematica but I have two problems. 1) The function is with z-Sqrt[z-1]*Sqrt[z+1] with z complex. Now Mathematica says that the ...
3
votes
2answers
102 views

Dealing with a sequence of function arguments that may contain lists

I have a function with multiple input parameters, Func[x1, x2, x3, ..., xm]. On occasion a subset of these parameters might be provided as a list ...
5
votes
2answers
83 views

Hiding independent variables of a function in Traditional Form

I would like to perform a computation which involves fourth-order derivatives of a composite function of four variables. I am defining my function as ...
6
votes
2answers
123 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
105 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
63 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
52 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
111 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
27 views

Symmetric properties of KroneckerDelta under replacement

The consider the following code: ...
1
vote
0answers
51 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. ...