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

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1
vote
3answers
275 views

Can I find constants in a function?

Let's say, I have a function with a constant, e.g. $y(x)=x+c$, and a condition $y(0) = 5$. I want to type in something like Solve[{y[x]=x+c, y[0] =5}, {c}] and get ...
16
votes
2answers
272 views

A bug in Commonest in version 10

Bug introduced in 10.0.0 and fixed in 10.0.2 m_goldberg demonstrated that in Mathematica 10 Commonest does not behave as the documentation indicates that it will....
0
votes
3answers
183 views

choose any number e that is relatively prime to n

I try to write a command that means choose any number e that is relatively prime to n, like e^n [Congruent] 1 (mod n), but it didn't give me a value of e. e^n [Congruent] 1 (mod n)
8
votes
2answers
306 views

Difference between Evaluation>>Quit Kernel and Quit[]

What is the difference between Evaluation >> QuitKernel and Quit[]? Both seem to quit the kernel (and clearing all ...
0
votes
0answers
46 views

Regarding Cycles and Lists of Functions

So, I'm trying to determine the Normal Matrix of a Least Squares Aproximation; I have a basis constituted by 8 functions f1,f2...f8; I have 9 points which constitute Datax = {x1,x2...x9} Now, I ...
0
votes
2answers
69 views

Binding trigonometric terms

I have many terms like A = Cos[Pi/18 + 2 x] + Cos[Pi/18 - 2 x] and I want to convert A to ...
1
vote
3answers
104 views

Defining a function using a preceding expression

How can I automatically define a function inside my Mathematica code using a result (expression) that preceded the point of definition. For example: ...
2
votes
1answer
184 views

Quantize a real-valued function?

I'm wondering if there's a built-in way in Mathematica to take a function whose output values are continuous, and quantize it to produce a step function. For example, I have the function ...
11
votes
2answers
301 views

How do I override options with my own defaults?

I'm calling a function f from within a function g and would like to pass any valid options for ...
2
votes
2answers
112 views

Define function over expression

Suppose I have the following expression system = x + y + z And I would like to define a function that contains this function, without explicitly typing the right ...
8
votes
1answer
152 views

How to sort the functions in a Package?

Once a Package like abc` has been installed, we can use "?abc`*" to scan all the functions defined in this Package. Now I ...
6
votes
3answers
255 views

How to define a nested function like this?

For example, I want to calculate the limit of $\frac{1}{1+\frac{2}{1+\frac{3}{1+\ldots}}}$. So I want to define: $f(1)=1$ $f(2)=\frac{1}{1+2}$ $f(3)=\frac{1}{1+\frac{2}{1+3}}$ Then I calculate ...
3
votes
0answers
69 views

Lists for built-in functions that can work without brackets

I just noticed that Exit and Quit can work without brackets i.e. a single Exit or ...
1
vote
1answer
103 views

FinancialData Input

What does the function FinancialData require as input for natural gas: http://finance.yahoo.com/q?s=NGG15.NYM Is it easier to export the natural gas data to excel,...
2
votes
1answer
284 views

How to make a function from body with variable number of arguments?

Suppose I have an UNKNOWN function, which generates formulas with given number of x[i]. ...
1
vote
1answer
237 views

Composition of Multivariable function

I am trying to compose functions of xleft, maybe like xleft[xleft[f]] or even higher order. And here is my function: ...
0
votes
1answer
78 views

Diffentiating a function f with respect to x [duplicate]

I have a tabe y={10,20,30,40...} and x={62,63,64,65...} y is a function f and this function needs to be interpolated. How do I defferentiate the function f with respect to x?
0
votes
1answer
73 views

Taking function output as shown, and processing it regardless of its history

I am making some symbolical calculations for my quantum chemistry class. I am supposed to build a wave function composed of multiple other functions, each of which is also composite of some lower ...
5
votes
2answers
9k views

How to tell Mathematica that certain variables are real/imaginary, integer-valued, etc

I'm trying to expedite some quantum mechanical calculations by running them through Mathematica. Expectation values and stuff like that. When I say, for example, ...
0
votes
1answer
60 views

What is the simplest way to obtain function obect of a given function?

Suppose I have a function p of some arguments: p[x_,y_]:= (* something *) Now I with to pass this function as an object to ...
1
vote
1answer
170 views

Why does LyapunovSolve solve non-standard form?

LyapunovSolve[A,Q] solves the equation $A P + P A^T = Q$ for $P$ whereas the standard form (wikipedia,lecture notes, p.25, linear control systems) of the Lyapunov ...
12
votes
1answer
376 views

Better Autocompelete for the Front-End

I wonder if it is possible to improve the front-end's autocomplete capability. Compared with some other more sophisticated editors/IDEs, such as eclipse, Mathematica's front-end does not provide a ...
1
vote
0answers
260 views

Crosscorrelation for nonperiodic signals

I want to detect patterns (of an absorption spectrum which is nonperiodic) with Mathematica automaticly. I have found CorrelationFuncion but as far as I understand, ...
1
vote
1answer
334 views

How can I call the R-programming packages in my Mathematica?

I am trying to call the R-programming package called highfrequency in my Mathematica so that I can use its function rCov. I ...
2
votes
2answers
380 views

cycloid parametric [closed]

How do I enter 3 parametric equations for cycloids corresponding to circles with radii 1, 2, and 4. I have tried ...
5
votes
3answers
168 views

Missing control for depth of Inner

Working on a mechanics problem, I stumbled on something peculiar: Since Inner is a generalisation of Dot, it changes its ...
1
vote
2answers
53 views

How to add a part of a list to a function?

I want to be able to add a specific portion of a list to a part of a function but this fucntion intakes 6 variables where as the list is of example: ...
2
votes
1answer
130 views

Show how Eliminate arrives at reduction

Does anyone know how to get Mathematica to show how it arrives at the following result? ...
-1
votes
1answer
467 views

Putting two functions in one manipulate plot

I have a problem that is somewhat related to this http://stackoverflow.com/questions/7727668/putting-two-plots-in-a-manipulate-whilst-keeping-the-plots-visible but I would like to plot two functions ...
1
vote
1answer
82 views

Help creating a simple function

Can someone help me to create a function. The truth I'm new in Mathematica and I don't understand well the way functions work in I. I need a function that animate some rectangles according to a curve ...
3
votes
1answer
83 views

Integrate[] does not work when the function has an antiderivative function

This function (1 + (1 + 1/(2*Sqrt[x]))/(2*Sqrt[Sqrt[x] + x]))/(2*Sqrt[x + Sqrt[Sqrt[x] + x]]) has the antiderivative function, since ...
1
vote
1answer
232 views

using a Mathematica function to define a new function

I'd like to define a function of three variables which produces a new, named function of a single variable, where this final variable is not a member of the first three. So I'd like something where I ...
1
vote
1answer
188 views

using Module in NDSolve

I am trying to solve a set of two wave equations where solution of first equation defines initial conditions for the second one. And I would like to use Module to define those equations as a function ...
1
vote
1answer
141 views

Apply functions to functions yields slow execution speed

I'm trying to write a function that parametrizes a curve c(t) by its arc length. Technicly I'm finished but if I plot the result for an example curve like ...
1
vote
0answers
40 views

Apparent issue with derivative of FractionalPart [duplicate]

This issue came to my attention from Math.SE: http://math.stackexchange.com/questions/1015325/is-the-derivative-of-x-on-0-1-always-equal-to-1/1015342#1015342 To summarize, it appears that ...
0
votes
0answers
182 views

simulate a 32-bit signed integer overflow in a recurrence function

Considering the following recurring equation: which is this factorial function: I want to find the value of x where f(x) = 0. Actually, the solution is impossible with Mathematica, and it's ...
6
votes
5answers
188 views

What is the shortest way to switch between heads of nested functions

consider this example: f[g[x]] what is the shortest way to switch between heads of nested functions to produce. g[f[x]]
4
votes
2answers
109 views

Function pattern to support listed and non-listed arguments [duplicate]

I often want to write functions that take as an argument either a) a rule or b) a list of rules. As an example, when using Replace with just one rule, it does not ...
1
vote
1answer
272 views

Error: in the part assignment is not a symbol [duplicate]

I am trying to set part of a Doubly-indexed list aInitialPopulation to cNumHeg. Specifically I am trying to set the 3rd part of the list aInitialPopulatiom[[cNodeNumber]] to cNumHeg. My (attempted) ...
2
votes
1answer
664 views

Using Integrate to define a function

I'd like to define a function by way of the output of a definite integral with symbolic bounds. For instance, F[m_,k_] := Integrate[x,{x,m,k}] would define ...
1
vote
0answers
69 views

RowReduce doesn't work for this matrix?

I have this matrix A={{0,1,1,w},{1,0,1,x},{-1,0,1,y},{0,1,1,z}} where w, x, y, z are arbitrary constants. This matrix should be row reduced to the form ...
13
votes
2answers
2k views

Which Mathematica function has the longest name (by character length?)

I came across DamerauLevenshteinDistance[u,v] in the documentation center so that got me thinking: Which documented Mathematica function has the longest name? ...
10
votes
1answer
347 views

Why does the documentation call functions “pure”?

Clearly, functions in mathematica are not pure functions according to the definition on Wikipedia (no side effects - basically implementabe with table lookups): ...
0
votes
0answers
48 views

Should this be equal to Gamma function or not?

I define the following function: Nat2[s_] := InverseFourierTransform[FourierTransform[1/t, t, w] (-I w)^(s - 1), w, x]/Cos[Pi (s - 1)] /. x -> 1 I expected ...
1
vote
1answer
142 views

handling division by zeros and line equations

today I was writing a code which takes some line equation and a circle equation,finds intersection points that are on $II$ and $III$ quadrants,draw a tangent line to circle from that point and then ...
1
vote
1answer
60 views

Multiway Systems Rules List Management

I'm working with a multiway system and I have a number of different mutation rule lists. I need an efficient way of managing which rule lists I apply. Here is the basic multiway system code that I'm ...
1
vote
1answer
105 views

Plotting a function in {X(Y),Y} space

The code below generates some data and defines a function f[x,cb]:=NMaximize[expr,x] that upon being evaluated returns: {function value at max $x$,the function maximizing $x$}. ...
15
votes
1answer
279 views

Why do big-O terms disappear in definite integrals since Mathematica 9?

In Mathematica 8, when I computed the following input: Integrate[Series[Cos[x], {x, 0, 2}], {x, 0, a}] Mathematica returned an expression that had a O[a^4] in ...
7
votes
2answers
210 views

How to redefine the type of multiplication in Det

I would like to redefine the type of multiplication that is used in Det (calculates the determinant). Instead of the standard multiplication I would like to use a custom function Fun[a,b] (which takes ...
1
vote
1answer
88 views

User defined functions and decimal places displayed

I have a couple of complicated user-defined functions, one which calls the other, and I wish to control the number of decimal places displayed when I call the "mother" function. I have tried the ...