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

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3
votes
2answers
301 views

Numerically finding a derivative jump of a function

How would I numerically find where a function has derivative jumps? In particular, I'm working with this function: ...
9
votes
4answers
848 views

Moving the location of the branch cut in Mathematica

According to the documentation, Mathematica chooses the branch cut for $\log(z)$ to lie along the negative real axis. It it possible to change this so that it lies along the positive axis or elsewhere ...
3
votes
1answer
338 views

Plot maximum and minimum temperature of a day for range of time interval

How to display (in any graphic representation) the maximum and minimum temperatures for one city in one of these selected time periods over the 5-day period? The time periods are: Morning (06:00 to ...
5
votes
5answers
760 views

Prevent Part[] from trying to extract parts of symbolic expressions

If you have a list, e.g. {1, 2, 3} then you can extract the $k$th part using Part (...
2
votes
1answer
1k views

How to define the Einstein summation convention in Mathematica?

How to define a Einstein summation convention in Mathematica? Say, how to let Mathematica know T[i,i] equals ...
2
votes
1answer
149 views

#[[1]]//FullForm = 1?

I have a set of symbolic algebraic expressions that I'm trying to get some speed into. To illustrate the issue, I'll use a simple form like { k0 X, k1 Y, k1 Z}, ...
1
vote
1answer
299 views

How do I define functions in TraditionalForm?

I'd like to be able to define functions (at least simple ones that Mathematica can otherwise understand) using TraditionalForm; but this seems to require the use of ...
10
votes
4answers
3k views

How can I differentiate Numerically?

Mathematica has two ways to integrate: Integrate and NIntegrate. But what about D? ...
2
votes
1answer
432 views

Cournot Equilibrium

I'm trying to determine reaction functions of a Cournot equilibrium for $n$ firms using the same optimal condition, using the fixed point method. This is the method I'm using: ...
0
votes
1answer
267 views

How do I numerically solve a custom function?

Whenever I use functions like FindRoot or NDSolve, it sends x through the function and deals ...
6
votes
1answer
293 views

GeneralMiniMaxApproximation - Dividing out the zero

MiniMaxApproximation is used to generate minimax approximations. I'm interested in the "dividing out the zero" trick. The documentation discusses a nice example. Suppose we want to construct a ...
1
vote
2answers
944 views

Interpolating a function of two variables

I am trying to create the interpolating function for a function of two variables, over a finite area. Just for consistency we can think of a function: ...
4
votes
3answers
3k views

Passing a function as an argument of another function [duplicate]

Possible Duplicate: Pass function or formula as function parameter I am trying to implement a simple Plot[]-like function, with the same synopsis; my first (and unique so far) try would be ...
2
votes
5answers
428 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 ...
6
votes
2answers
394 views

A command for outputting a list of parameter values in a Manipulate interface

I am looking for a command that will output a list of values that correspond to the current parameter values manually set on a particular Manipulate interface. For ...
4
votes
2answers
688 views

How to make a function that evaluates an expression?

I'm trying to make a function where the input is an expression, but somehow it just won't be evaluated. For example, this little function doesn't work: ...
2
votes
1answer
479 views

Plugging values into functions

I am very new to Mathematica, and need to know how to plug values into existing functions. For example, Math World supplies the following code for building a truth table of ...
2
votes
1answer
312 views

About high dimensional integrals

I want to be able to do high dimensional integrals like, (..naively I wrote it as this..) ...
4
votes
3answers
416 views

Generate a Combination of letters by a number

I'm trying to write a function f. example: ...
2
votes
1answer
378 views

Creating a matrix from the output of a variable inside a for loop

I would like to enter the results of the following loop inside a matrix as its elements: ...
1
vote
2answers
150 views

How to mix Unevaluated property of function arguments with expression assignments?

This is a follow-up to my (solved) question How to distribute a generic function of two arguments (without evaluating the arguments) Say, I have a binary function ...
12
votes
1answer
353 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 ...
10
votes
3answers
468 views

Why does Hash return different values in Version 7?

This function does not work correctly for me. The generated Gravatars do not match the ones actually produced by using the corresponding address. The problem was traced to differing output from the ...
3
votes
2answers
3k views

Plot Even Piecewise function

Is it possible in Mathematica to plot an even piecewise function like: $ f(x) = \begin{cases} 3t , 0 \le t \le \frac{\pi}{2} \\ 3t + 6 , \frac{\pi}{2} \le t \le \pi \end{cases}$ which has ...
4
votes
3answers
200 views

How to distribute a generic function of two arguments (without evaluating the arguments)

I guess there is an easy way to do this, but I can't seem to figure it out. What I would like to do is to distribute a generic (i.e. without specifying what this function really does) binary function. ...
0
votes
1answer
393 views

How to create function that classifies sample data

I want to create expression, that classifies samples ( 4 weather features -> decision). Example training data: For the values that i have data for, I can use rules: ...
4
votes
2answers
270 views

How can I use Max[] in a function that is passed a list not find the max of the list

For most functions in Mathematica, passing them a list will call the function on each element of the list. For example: ...
1
vote
2answers
87 views

Using non-Graphics primitives when exporting to .cdf

I'm trying to embed a "Manipulate" applet I've created into a webpage by embedding a .cdf. I'm running into a problem with displaying outputs from functions I've written. Here is a simpler example ...
4
votes
3answers
1k 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 ...
3
votes
3answers
437 views

How to pull scalars out of a function that should act on lists?

Suppose I have A = a vecA B = b vecB where a and b are supposed to be arbitrary scalars ...
3
votes
3answers
211 views

How to set a function as a parameter?

In case I want to know whether a given function $f(t)$ have some property, I tried to write something like this: ...
7
votes
1answer
527 views

Demonstrating Ackermann's Function

The Ackermann function is an extremely fast growing function. There are some slightly different versions of the function, but the one that I am looking for can be defined as: $$ A_0(x)=x+1 \\ ...
29
votes
3answers
694 views

Parentheses in pure functions: # & vs. ( # &)

I've been using Mathematica for years, and over time I have developed the habit of using: Select[data, (# == 1 &)] instead of ...
4
votes
1answer
2k views

How can I save and recall my own function?

In MATLAB, I can save and recall my own function using an M-File(function or script) How can I do something similar in Mathematica? I already searched and know how to define functions and modules ...
4
votes
3answers
3k views

Map w/ multiple arguments [duplicate]

Possible Duplicate: How do I use Map for a function with two arguments? If I have a function: F[x_,y_,z_]:=x*y*z and I want to call it with several ...
4
votes
2answers
311 views

Plotting two functions with dependent input function

I have defined a function: myJ2[n_] := 1/n* Total[RandomVariate[NormalDistribution[0, 1], n]^2] This is basically an approximation to the gaussian integral. I ...
11
votes
2answers
993 views

NestList on a function of several arguments

I'd like to know if it is possible to use NestList on a regular function of several arguments, such as: ...
3
votes
1answer
2k views

Nested If statements

When I do this: Apply[(If[#2 == what, "yay", If[#2 == whoops, "nay"]]) &, {-5, what}] I get: yay But when I do this: ...
3
votes
2answers
420 views

Handling Indeterminate Forms

I'm running a sum, the elements of which are calculated by calling functions that I wrote. The only issue is, I've implemented this pretty stupid solution where I have 4 or 5 (nested!) if statements ...
4
votes
1answer
279 views

How to organize and run functions?

I am very new to Mathematica. I thought I would try it out for my first assignment in my computer science class. Until now I have only used C-base languages including C#, Java, Objective-C, and ...
8
votes
1answer
344 views

ReplaceAll[] and Limit[] don't give correct results for this expression under extreme variables [duplicate]

Possible Duplicate: Funny behaviour when plotting a polynomial of high degree and large coefficients 1/x^2 + (3 + x)/(6 (1 - Exp[x] + x)) ——This is a ...
1
vote
1answer
168 views

Computing a logarithmic function

Possibly this is a very lame question for this site. There is a function $f(n)=-\ln(a*n); \space \Bbb Z \to \Bbb R$, and I want to define $a$ for pairs of values. For example: $f_1(n_1)=15; ...
4
votes
4answers
649 views

How to define and use a linear function

I have the following equation $T = -800n + 12000$. I know that this is a linear function and that the two points $(0, 12000)$ and $(15,0)$ lie on the line. When I have 2 other values of n between 0 ...
1
vote
2answers
390 views

Piecewise function with a function as argument

I want to define a piecewise function, which has two arguments, one of which is a function of the other's piecewise argument. I am giving an example ...
1
vote
2answers
151 views

How can define a set of nested parameters

I would like to know how I to define a function with a nested set of parameters (or whatever you would like to call it). For example, how would I get the following function ...
1
vote
3answers
1k views

Variables Inside Functions Not Evaluating

x = 5*y function1[y_] := x function1[5] Am I wrong in thinking that function1[5] should equal 25? Instead this comes out. ...
2
votes
1answer
170 views

Using an InputField to define a function to compose with a sequence

I am still trying to figure out Mathematica (started early August). I am trying to write a program that will accept an arbitrary function and an arbitrary sequence that can start at an arbitrary ...
5
votes
3answers
251 views

First evaluation fails

I am fairly new to Mathematica (version 7), so please bear with me... I have duplicated, in Mathematica, a program that I originally wrote in C (it generates OEIS sequence A191837). The problem is ...
19
votes
8answers
655 views

Applying And to lists of Booleans

I'd like to take {True,True,False} and {True,False,False} and apply And to get ...
14
votes
7answers
384 views

Get the first element after the first sequence of length N of consecutively increasing values

I'm looking for an efficient way of extracting the first element after the first sequence of N consecutive elements in which the values are increasing. If these are the data of a toy example: ...