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

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-4
votes
0answers
33 views

About functions of a matrix [on hold]

I have a matrix problem. My question is: $f(x) = 3x + 1$, find $f(A)$, where $A = \left(\begin{array}{} 1 & 3\\ 2 & 0\\ \end{array}\right)$.
1
vote
1answer
54 views

LinearModelFit: How to compute R-squared? [on hold]

Is there a simple way to computed the R-Squared(adjusted and not adjusted), from the LinearModelFit? It has so many options, but none for the R-Squared, that I suspect there's a simple way to compute ...
1
vote
1answer
76 views

Double arguments and place of the underscore

Could someone explain me of this bit of code below is correct: Is it possible to define a function with a second bracket, see below, i.e. f[x_][y_]? And what does ...
1
vote
1answer
43 views

How to properly plot a unit pulse? [duplicate]

I am using this function to plot ...
17
votes
5answers
419 views

Partitioning a list when the cumulative sum exceeds 1

I have a long list of say 1 million Uniform(0,1) random numbers, such as: dat = {0.71, 0.685, 0.16, 0.82, 0.73, 0.44, 0.89, 0.02, 0.47, 0.65} I want to ...
1
vote
1answer
54 views

How do I write a function inside a ArgMin

I want to solve this ArgMin[NIntegrate[(Tanh[x] - Erf[x/a])^2, {x, -5, 5}], a] and it does not work, what is the correct way to do this? ...
-2
votes
0answers
70 views

I need to write an animation of something l [closed]

I need to write an animation of something like this: [![enter image description here][1]][1]
1
vote
2answers
42 views

using Map to apply 2 lists to the LCM function - help [duplicate]

I have 2 lists of numbers and I want to quickly compute the array of answers to the LCM function for the 2 lists and a 3rd static number. I tried the following ...
1
vote
0answers
77 views

Using functions in Solve [closed]

i wanted to calculate the real roots of a function. To my knowledge the function i defined has no real roots, so i expected an emptyset, but instead i got some Root[...#..] answers by Mathematica. ...
0
votes
0answers
48 views

Personal Reminder with Speak capability repeats multiple times

I am trying to create a personal reminder for myself using the Speak function in Mathematica hoping that the computer speaks the task only once at the designated time. However, I have found that the ...
2
votes
1answer
96 views

Find a family of curves

I have a diagram with seven curves (each with a different parameter). My goal is to find a function for the family of curves (i.e. a single function not just for the seven parameters, but for all ...
2
votes
2answers
59 views

Multiple functions with shared arguments in Manipulate

I am trying to define multiple functions with the same set of parameters and then put them in a Manipulate to simulate their behavior. Ideally it should be something like that: ...
0
votes
1answer
44 views

How to apply a user-defined function to a list [closed]

I'm using Wolfram | Alpha Pro; I have a function f[n] = 351n^(-0.7); How do I apply it to each element of a list like {2, 9, 22}? f/@{2, 9, 22} just results in ...
6
votes
2answers
117 views

Getting an explicit representation of the function returned from Interpolation [duplicate]

I am using Interpolation to get an InterpolatingFunction that fits a set of points. For example, ...
-1
votes
0answers
44 views

How to calculate the value of financial derivatives [closed]

I want to loop through all of the put and calls available for each of the derivative types as listed by calling: FinancialDerivative[] I need to eliminate the ...
5
votes
3answers
143 views

How to tell Mathematica to get the real-only inverse function?

The problem I have is that Mathematica seems to play better with complex numbers so that the result of N[InverseFunction[Function[x,x^3]][-1]] is ...
0
votes
1answer
43 views

Interpolate the discrete list into continuous function

I have a data whose list plot shows up following graph I would like to interpolate the missing data and make the function continuous but for particular x-coordinate there is multiple values of $y$ ...
3
votes
1answer
65 views

Are these two functions equivalent?

I checked several cases and saw that two functions are equivalent in these samples. However, are the two equivalent in all cases? Is there a way to check that? Explicit function: ...
1
vote
0answers
28 views

Function with many lines that takes image as parameter not returning same result as if I run the same lines of code

Running the exact same lines of code in a function produces just a return of the original image without any points identified, whereas when I run the exact body of the function line by line it works ...
0
votes
3answers
59 views

How to find the value of a variable using solution of Simultaneous equations? [closed]

I have to find the value of p where p=a1*x+b2*y; using the solution of the equation ...
1
vote
0answers
89 views

Need help interpreting a small block of code [on hold]

I have recently "inherited" some Mathematica scripts which I need to interpret to write in some other languages (Maple and C++). I have never used Mathematica before so I have been learning on the ...
3
votes
1answer
64 views

Define a function with multiple lines mathematica [closed]

How is this done? ...
1
vote
2answers
65 views

defining a function using other functions

I have the following code: ...
0
votes
0answers
73 views

Errro in plotting the results of FindRoot [on hold]

I would like to plot the results of FindRoot over certain range of one input. First of all I am sorry that the equation is a bit long and messy. I have tried to ...
1
vote
1answer
104 views

The basic primitive recursive functions

How can the basic primitive recursive functions be expressed in the Wolfram Language? Apparently here's an example for primitive recursion: ...
3
votes
1answer
49 views

A function about prime gaps

I want to define a $f$ function on Mathematica such as this. $f[k]$ gives the smallest $m$ holds $2k=Prime[m+1]-Prime[m]$. For example, $$f[1]=2$$ $$f[2]=4$$ $$f[3]=9$$ $$f[4]=24$$ How can i do ...
1
vote
1answer
52 views

Building functions using WolframAlpha? Any other general examples welcome :)

I want to build my own version of SubsetQ using WolframAlpha to return True or False. ...
4
votes
1answer
163 views

Goal optimization: finding the best combination of capacitors and resistors resulting in given properties

I want to edit @MarcoB answers (because the code he gave doesn't answer the question appropriately)->(the function that need to be optimised is not implemented as asked) But it seems like I am having ...
0
votes
1answer
34 views

What is the function “oneflag_:0” in this expression? [closed]

The first function Pivotdown can zero out all entries in a column below a desired location. But l don't know the function of “oneflag _0".
0
votes
1answer
37 views

If Statement in function does not evaluate

I've written a function that should try to simulate a "triangle-wave-signal", given a few parameters. It looks like this: ...
0
votes
0answers
73 views

How to change the built-in function? [duplicate]

As you can see,the original Differences will get {} when your parameter is a list with one element just. Differences /@ {{1, 2, ...
12
votes
2answers
380 views

Fitting a curve to an image object: not a superellipse, not an egg curve.. what else?

I'm facing the problem of quantifying the morphology of objects with such a shape (nannoconids... they are fossils). One of the final goals is to produce a solid of revolution and compute ...
3
votes
2answers
36 views

How to add Optional Sequence

Note: This question could be duplicate but I couldn't find any so far. It is know that Optional (:) can be use to represent expression if omitted. ...
0
votes
2answers
50 views

How can I put a defined symbol as the integrand of NIntegrate, without using a functional form with a pattern test?

Something like this, I define an integrand (really big and hairy, simple below) ...
1
vote
1answer
31 views

Oddity with ToExpression [duplicate]

Is this a bug? ToExpression["3231.432"] 3231.43 I would have expected the following: 3231.432 I am using Mathematica 10.2.0
0
votes
1answer
28 views

Simplification of rational function with Assume function [closed]

I didn't manage to simplify this expression : Simplify[Assuming[x > 0, -((2 Sqrt[x^2/(1 + x^2)^2])/x)]] Do you have ideas why the simplification is not ...
3
votes
1answer
79 views

Map if-function on a list

I need to convert a battery charging mechanism from Excel into Mathematica. This Excel function is about deciding if the charge/decharge rate is positive, then multiply with efficiency factor, ...
9
votes
1answer
274 views

Interpolation function way off

I have a simple list of data points to which I would like to fit an interpolation function. However, the results given by Interpolation[] gives an oscillating function which is not warranted by the ...
5
votes
2answers
189 views

Results in terms of a function

Let's assume I have a function $f(x)=\exp(10x^2)$, i.e. f[x_]:= Exp[10*x^2]. When I differentiate $f$ by evaluating the expression ...
3
votes
2answers
116 views

Discritizing an analytical 3D-function

I have the following Problem: I need a discretized amount of points in a 3D-volume. These points satisfy a condition to built-up a 3D-geometry. In my example below I selected a helical geometry. The ...
5
votes
1answer
80 views

Same name for functions in package and Global context

I am using a package that was written for Mathematica 3 while I am now working on Mathematica 8. I have issues with 2 functions in particular, Order and GraphComplement. They are a part of this ...
4
votes
1answer
55 views

Strange behavior of ArcTan [duplicate]

I've noticed a strange behavior of Mathematica's ArcTan function with two arguments. If both arguments are 0 or ...
7
votes
6answers
487 views

Partial sum of a list

The problem I have is really basic but I just can't get my head around it. Suppose I have a list of ordered pairs A = {{a, b}, {c, d}, {e, f}, {g, h}, ...}. I ...
2
votes
1answer
76 views

Inputs which make two function have the same value [closed]

Suppose I have two function f(x1,...,xN) and g(x1,...,xN). How can I find the values ...
0
votes
1answer
117 views

For-loop function problem [closed]

I wrote the following true anomaly function based on a Fortran program that I found in a computational space flight dynamics book. The function uses an iterative method to calculate the true anomaly ...
17
votes
0answers
122 views

V10's TypeSystem - what are these function useful for? [closed]

The symbols in the TypeSystem` context are clearly used for working with Datasets, but they seem powerful. I was hoping that someone could help explain how they work and is they are useful for ...
5
votes
1answer
129 views

Attributes with Pattern test

Probably this question has no application but it helps understand basic issues about Attributes and functions. I was writing a piece of code where I accidently ...
5
votes
1answer
119 views

How to make my fuction return a step count

I am new to mathematica, and I have this 3d random walker program which runs with a fixed (given) amount of steps. What I want it to do is to run forever but stop when two walkers collide (aka have ...
2
votes
1answer
62 views

Finding the expansion of $\sin(a_{1}+a_{2}+a_{3})$ on Mathematica [closed]

How to find the expansion of $\sin(a_{1}+a_{2}+a_{3})$ on Mathematica, using $$ \sin(a+b) = \sin a \cos b + \sin b \cos a$$ to the end? I tried FunctionExpand ...
0
votes
0answers
65 views

Finding double inverse Laplace transform numerically

Edit: I asked Prof. Valko, he was so nice to point out where the mistake is. The problem is solved ! Thank you for your attention ! Recall the the double Laplace transform of a function $f(x,t)$ is ...