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

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15
votes
2answers
276 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
131 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 ...
1
vote
1answer
352 views

Finding n-th term of a sequence of functions

Lets say, I have the following series of functions, $f_1=a+1$ $f_2=a^2+2a+1$ $f_3=a^3+3a^2+3a+1$ Assume that $f_4, f_5,$ and $f_6$ are also known. However $f_n$ is not known as a function of $n$. ...
13
votes
1answer
320 views

How do I get a general form for n-th derivative of a function? [duplicate]

I tried the following but it basically returns unevaluated: ...
1
vote
1answer
224 views

Notebook UI: Autocompletion - Display function arguments when typing?

Is there a setting to display the required arguments of a function when typing as Visual Studio, Matlab, etc. does?
2
votes
1answer
149 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 ...
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
97 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., ...
2
votes
1answer
1k views
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 ...
3
votes
2answers
151 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: ...
2
votes
2answers
678 views

distance between two curves

I try to compute the distance between two curves. I use the EuclideanDistance to do that. Here my code: ...
0
votes
1answer
338 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 ...
0
votes
1answer
114 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
2k 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
571 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 ...
5
votes
5answers
2k views

How to sum over a List

list = {11.5575, 11.397, 5.52734, 4.0878, 2.54815, 1.86652, 2.55028, 2.14952, 1.6242, 1.34117} I have a list of numbers. How do I make a function that creates a ...
1
vote
1answer
389 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)) $ ...
2
votes
1answer
947 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
123 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 ...
0
votes
0answers
32 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 ...
1
vote
1answer
820 views

Plotting a complex function [duplicate]

What does it mean if this message appears: {Im[(1-E^Times[<<3>>] f)/(1-Power[<<2>>] f)]-0,Im[(1-E^Times[<<3>>] f)/(1-Power[<<2>>] f)]-0} must be a list of equalities or ...
5
votes
5answers
2k views

Series expansion in terms of Hermite polynomials

I am trying to expand a polynomial in terms of orthogonal polynomials (in my case, Hermite). Maple has a nice built-in function for this, ChangeBasis. Is there a ...
10
votes
5answers
358 views

Transform a list of functions to a composition

How do I apply a list of functions in a nested way? Example: functionList = {f1,f2,f3} RequiredCommand[functionList,Pi] such that the required command returns ...
2
votes
1answer
136 views

Obtaining a function from the function

Assume that; ...
1
vote
1answer
190 views

FindMaximum inconsistency

The code below seems to work for n<11. But for n=11, and above, it outputs newa then just outputs "beep" sound. WhyTheBeep says "The kernel Local has quit ...
0
votes
1answer
103 views

Should Read[] not close its Stream? [closed]

I read a record from a file. Read[file,Record]; It reads and opens a stream. Should Read not close its stream after ...
3
votes
3answers
210 views

Alternative to using global variables in functions?

Often times I find myself using unevaluated variables (i.e. they show up blue) as dummy variables in whatever I'm returning such that I can evaluate them as needed later on. A simple example is as ...
19
votes
4answers
742 views

Accessing list elements by name

First, a bit of a long introduction to my problem: I only have a few weeks of Mathematica experience. I am creating a mathematica application that calculates some material properties of steel based ...
2
votes
0answers
124 views

Is there documentation on the comparative performance of Mathematica functions? [duplicate]

Recently I have been solving some Project Euler problems. I find there are always several ways to do the same thing. For example, one could join two lists like this: ...
12
votes
1answer
270 views

Is there a summary of answers Head[] can give?

Sometimes you need to check for the type of an expression. You use Head[data] to get answers. Some data: ...
0
votes
1answer
66 views

how to generate functions with changing array size?

I want to write a function in Mathematica which has two inputs 'n' and 'd', and the output should be (in Latex notation) $$F(n,d) = \sum_{i[1],...,i[n] =0; i[1]+...+i[n]\leq d}^{d} C[i[1],...,i[n]] ...
3
votes
2answers
2k views

Define a color function using Piecewise

How can I define a ColorFunction for my ContourPlot using Piecewise? For example after ...
10
votes
5answers
816 views

Building a continued fraction

I've completed a problem that involves approximating $e$ by a continued fraction: $$\frac{N_1}{D_1+\frac{N_2}{D_2+\frac{N_3}{\ddots+\frac{N_k}{D_k}}}}$$ with the $N_i$ being the list ...
0
votes
2answers
344 views

Expansion in Basis Functions

I am trying to create an expansion of the form f[x,y]->Sum[Cn[x] y^n,{n,1,order}] To replace the function f by the ...
0
votes
1answer
185 views

Solving a differential equation for a variable in a function

This may sound like a very trivial question, but I need to solve a differential equation as follows: ...
9
votes
2answers
325 views

How can I get the right hand side of a delayed expression?

Imagine there is a given function f, defined with SetDelayed, say f[x_] := Sin[x]^2 + Cos[x]^2. Is it possible to get rhs of ...
0
votes
0answers
41 views

Define a Plot3D function with custom options [duplicate]

I am trying to define a Plot3D function with custom options, following (this previous SE question), but I'm running into a brick wall. I've narrowed the problem to the following 'toy' code: ...
4
votes
2answers
177 views

How to use ScientificForm in computation

Lets say I want to add 2 values : ...
1
vote
0answers
54 views

Confusing efficiency and evaluation when returning pure functions? [duplicate]

I have a function that takes some time to evaluate, that's meant to be a polynomial approximation to a function. The polynomial is defined by a list of coefficients, so I have the function ...
16
votes
4answers
7k 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)} ...
1
vote
2answers
125 views

Named patterns as function argument descriptors

I have a function timeToMinutes that takes a 24-hour time as a string argument (in digital clock format, e.g., "15:47") and converts it to the number of minutes ...
2
votes
1answer
524 views

Problem using the DifferentialEvolution method of NMinimize [closed]

I have a function of 20 parameters, which 3 of the parameters are my physical parameters, and the others are pull terms to fix the errors. The goal is finding the global minimum of this function, to ...
7
votes
4answers
728 views

How make f[{x,y}] evaluate as f[x,y]? [duplicate]

I frequently encounter the situation where I have a function of two real variables defined, e.g.: f[x_, y_] := 9 - x^2 - y^2 But then I need to feed into ...
5
votes
2answers
644 views

Is there an $n^{\text{th}}$ root function in Mathematica?

Is there a way to find $\sqrt[n]{x}$ with Mathematica beside of x^(1/n) as this is something different, because this is not always the same $$(-1)^{\frac{2}{4}}=i ...
3
votes
4answers
838 views

Extract function arguments

Is there a way to extract the arguments of a function? Consider the following example: I have this sum ...
3
votes
2answers
349 views

Why does the first derivative of a piecewise continuous function have discontinuities?

I have this piecewise continuous function which is also continuously differentiable over time : ...
6
votes
1answer
197 views

Does pass-by-value affect the performance of function calls?

I only have a little coding experience in C, and I remember I was told that pass by reference is more efficient than pass by value since the parameters don't need to be copied. Since there is no pass ...
23
votes
4answers
559 views

Enforcing correct variable bindings and avoiding renamings for conflicting variables in nested scoping constructs

Using global variables the following turns an "expression" into a Function: expr = 2 x; Function[x, Evaluate[expr]] Of course ...
1
vote
3answers
1k views

How do I create a matrix of functions?

I'm trying to create a matrix in which the elements are functions of two variables, but I can't figure out how to do it. Is it possible? The only way I could figure out is to define the matrix in ...