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

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6
votes
3answers
298 views

How to get the correct answer when solve this equation?

I want to find the values of the parameter $m$ to the graph of the funtion $$x^4 - 2 m x^2 + m + 1$$ has three extremal points make an equilateral triangle. I tried ...
1
vote
1answer
150 views

Recursive function taking functions as arguments

I'm trying to implement Lie brackets and derivatives of nth order. For doing this, I've stumbled upon something I don't understand. Here is an illustration: First I define the functions: ...
9
votes
1answer
365 views
7
votes
2answers
139 views

Change some option of a function when calling it [duplicate]

Say I have defined some function like f[p_] := Plot[Sin[p*x], {x, 0, 2 Pi}] Now in most cases, I just need to specify the value of ...
1
vote
1answer
149 views

Find a sequence of integers which give max in each step

I would like to write a program in Mathematica to look for the integer $n$ such that the following definition holds for any $1 < m < n $ $$\frac{f(n)}{f(m)}>1+\frac{\log(n/m)}{\log(n) ...
-1
votes
1answer
243 views

How to define a pure function with a Module?

I was not able to use a self defined (using Module and For loops) piecewise function to fit data. It seems that the problem is that I have to define a pure function. I would like to learn how to ...
4
votes
1answer
339 views
16
votes
2answers
1k views

Sum or Product with Exclusions

Is there a built-in feature for handling things like: $$\sum_{i=0}_{i\ne j}^n\frac{a-a_i}{a_i-a_j}$$ and $$\prod_{i=0}_{i\ne j}^n\frac{a-a_i}{a_i-a_j}$$ or should I work out some sort of ...
2
votes
4answers
1k views

How can I create a list of functions?

Can anyone tell me, how to create a list of functions? I've tried the following code, but it doesn't work. ...
35
votes
2answers
4k views

What is so special about Prime?

When we try to evaluate Prime on big numbers (e.g. 10^13) we encounter the following issue : ...
24
votes
1answer
232 views

What does Internal`InheritedBlock do?

What does the function Internal`InheritedBlock do? How is it different from the regular Block?
0
votes
1answer
65 views

Have the kernel load a user-defined function by default [duplicate]

I wrote a very simple function that I would like to act as if it were one of the default functions that came with Mathematica, so that you don't have to load or import any package before you make use ...
6
votes
1answer
114 views

create function that behaves like continuedFraction [duplicate]

I'm just starting to learn Mathematica and I got stuck at this question. This a noob question but please help. I need to define a function named continuedFraction that takes user input of type list ...
3
votes
2answers
766 views

Function returning Null along with other unexpected expressions

When I use some function, at the end along with the output I get some NULLs returned that I don't understand the reason for and are highly undesirable. For example, when I define the reversal of list ...
1
vote
0answers
85 views

Does Graphics`Mesh`SimplePolygonQ[] work for you?

Graphics`Mesh`SimplePolygonQ is an undocumented function. I'm using Mathematica 7, and when I try: ...
0
votes
1answer
77 views

What does Binomial return for non-integer arguments?

Mathematica returns values for non-integer arguments passed to Binomial. What is the definition of Binomial for such continuous ...
2
votes
1answer
116 views

Flat function with repeated sequence

There are functions like Join[ ] that accept a variable number of arguments. Join is a flat function, as the order of arguments ...
16
votes
4answers
6k views

Finding Limits in several variables

Is there a way to find a limit of a multivariable function, like $$\lim_{(x,y)\to (0,0)} f(x,y)$$ with Mathematica? When $f$ is continuous, we can use $$\lim_{(x,y)\to (0,0)} ...
9
votes
1answer
193 views

Creating a NearestFunction that returns an index

I use Nearest repeatedly for large data sets. For example pts = RandomReal[{-1, 1}, {1000, 3}]; Nearest[pts, {0, 0, 0}] I ...
3
votes
0answers
165 views

Mathlink and multithreading

In order to make my computations faster I have developed a C/C++ application calling Mathematica kernel and performing many operations using Mathematica functions for equation solving. Now I want to ...
4
votes
2answers
363 views

Cannot call custom function loaded from script using C/C++ MathLink

I am using MathLink with C/C++ on a Unix system in order to call a Mathematica (version 9) function and get the result. The function I need to call is a personal function of mine ...
9
votes
1answer
231 views

Apply a Function Pairwise

I'm new to Mathematica I'd like to apply Mean pairwise to a list to achieve the following. ...
1
vote
1answer
163 views

How to send a function definition to MathLink from C/C++?

In this tutorial some MathLink concepts are introduced. At page 33 in the last lines the author is talking about sending to MathLink a function definition like ...
6
votes
1answer
113 views

How does `LongestCommonSubsequence` work?

When I recently came across this posting about LongestCommonSubsequence I was curious about how the function worked. ...
15
votes
2answers
249 views

What are Root objects with multiple polynomials?

In Mathematica 9 a new flavor of Root object with multiple polynomials was introduced. For example, ...
10
votes
1answer
129 views

How do I expand StirlingS2[n, 10] in terms of elementary functions?

I know that it is possible to expand StirlingS2[n, 10] in terms of elementary functions of n. I tried ...
13
votes
1answer
288 views
2
votes
1answer
135 views

Cannot run Mathematica C-interfacing examples 'factor'

I am trying to run a Mathematica example concerning Mathematica interfacing issues with C programs. In particular I am trying to call a Mathematica function from C. Example ...
2
votes
3answers
385 views

Use elements of Array inside function definition

I'm trying to define a function which modifies and sums over the elements of an array. Here is a very simplified version. myF[kmax_] = Sum[v[[k]]/k, {k, 1, kmax}] ...
0
votes
1answer
62 views

Don't pollute outside context when solving equation from the outside

This code works fine only if a is not defined in the outside context: ...
1
vote
2answers
95 views

Calling blank arguments using enclosing functions

Is there a way to call a function and have that function use an argument defined in an enclosing function? e.g., ...
11
votes
1answer
1k views

Write C/C++ programs calling Mathematica functions

I need to write a C/C++ program and call some functions in Mathematica especially those like Solve or NDSolve. The problem is ...
2
votes
2answers
623 views

distance between two curves

I try to compute the distance between two curves. I use the EuclideanDistance to do that. Here my code: ...
3
votes
2answers
504 views
3
votes
2answers
136 views

Generating a list of pure variables

I want to pass a list of pure variables to a function, in which the ordering of the variables matters. For instance, if I want a palindrome, my function might be: ...
0
votes
1answer
297 views

Can Mathematica check if two expressions give the same output for integer input?

Let me give the background for this question. I'm using WebAssign to assign homework problems, and WebAssign has a built-in mechanism which can grade problems using Mathematica commands. For ...
2
votes
5answers
403 views

How to leave function unevaluated programmatically?

Is it possible to write a function in such manner, that it can be either evaluated or left unevaluated? This is a general question. Sample below is just a sample. No need to find solution for this ...
4
votes
1answer
169 views

Create string from character code

Is it possible to convert a charcode/keycode to a string? I want to do this to create variables in a generated equation.
0
votes
1answer
111 views

Can I force a function to quit and return some value after a certain amount of time has passed during its evaluation?

Imagine I provide some random input to function like FindInstance[], and I observe that, despite the existence of good solutions, the function will, with some ...
1
vote
1answer
1k views

How do I define the domain of a function?

I have a function of two variables, f[x_, y_], and I would like to restrict the domain to values of x and ...
1
vote
3answers
508 views

Sqrt — how to get negative branch?

One of the many attractions of Mathematica is that integers are generally treated as exact symbolic entities, and not just as numbers. I was just playing with Sqrt, and was puzzled by what appeared to ...
7
votes
2answers
495 views

Function Interpolation with Automatic / Algorithmic Values Mesh

I have an underlying function f(x,y,z) that is computationally intensive, but is smooth and continuous. I'm needing to find the function values along a line in xyz. Currently, I'm calculating f at ...
0
votes
1answer
318 views

Using undefined function in an expression

I want to use undefined functions in expressions to be simplified. For example. I want mathematica to simplify this input $(f^{\prime\prime}(t),g^{\prime\prime}(t))\cdot (-g^\prime(t),f^\prime(t)) $ ...
1
vote
1answer
857 views

3D plot of two 2D functions

I would like to plot two 2d functions in a 3d coordinate system. Examples are z = x^2 and z = y^2. Each function has one ...
2
votes
2answers
113 views

changing a symbol into a function variable

Struggled for a while on this problem and hopefully you can help... I have a mathematical expression that currently has a symbol where I used to have a function variable. How do I make the symbol ...
9
votes
1answer
498 views

What is the difference between prefix/postfix notations and map?

I am new to Mathematica and just experimenting with the different programming constructs. I have been looking at Map and how to evaluate a function for a list of ...
4
votes
3answers
995 views

How to prove an expression by method of mathematical induction?

I want to prove the expression $$1^2 + 2^2 + 3^2 + \cdots + n^2 = \dfrac{n(n+1)(2n+1)}{6}$$ by method of mathematical induction with Mathematica, but I do not know how to start. How do I tell ...
0
votes
0answers
28 views

How does Plot evaluate its argument? [duplicate]

I have a list of about twenty InterpolatingFunctions that I'd like to plot. They are interpolations from experimental data (frequency spectra between 100 and 5000 ...