# Tagged Questions

Questions on correct (or improved) formulation of Mathematica code to achieve particular results. Use this tag (not "symbol") for questions about all those odd @@ /@ # & and ~ characters.

69 views

### Mathematica Empty Plot FourierSinSeries function

I'm trying to get a plot of different order Fourier series of the function x-1, why does Mathematica give me an empty plot? ...
4k views

### How do I increase the readability of this code?

Below is some code I am working on; being a beginner. How can I increase the readability of the part behind Manipulate? I can't read my own code anymore, because it is simply too long and unordered. ...
859 views

### Using Transpose with a list as the second argument

I'm having difficulty understanding the Transpose function. I know what the transpose of a matrix is, not a problem, and I see that applying the ...
3k views

### Flatten command: matrix as second argument

One thing I could never wrap my head around is how Flatten works when provided with a matrix as the second argument, and the Mathematica help isn't particularly ...
64 views

### How to create assignments to OverVector programmatically

I wish to write a function that accepts two lists. The 1st argument is a list of lists, holding the components of a several vectors. Ex.: comp = {{a, b}, {c, d}}. ...
179 views

### How to avoid repetitive calculation when doing numerical integral?

Suppose I have a function f[x] which is very complicated, together with a function g[f[x]]+h[x] to integrate. That is: ...
15 views

### How to evaluate a function for a parameter with a range of values? [closed]

I have a function given below ...
41 views

### Simple list manipulation [closed]

I have two lists: {1,2,3} and {a,b,c} and I want this result: {{1,a},{2,b},{3,c}}. What is the right command? How does one call such an operation?
212 views

### Should I add a semicolon after a function definition? [duplicate]

should I write the program like this: f[x_]:=x^2; g[x_]:=x+2; or should I write the program like this: ...
141 views

### How to calculate this probability?

Here I want to find the probability $p$ which is given by $$p=\int_0^{r_d}\mathcal{L}_I(\beta r^{\alpha}|r)f_R(r)dr$$ with $r_d=1$ and $0 \le r\le r_d$. I want to calulate the probability for ...
71 views

### Grouping/precedence for “/@” operator

This returns errors: {#[[1]],#[[3]]} & /@ {#[[1]],#[[2]],#[[3]]} & /@ {{"A","B","C"},{1,2,3}} Part::partd: Part specification A[[1]] is longer than ...
283 views

### Finding the position of a specific value in a list

Is it possible to easily find the position of a specific value in a list? For example, if the list is {{x1,y1},{x2,y2},...,{xn,yn}} I would like to know the ...
140 views

### Plotting an equation describing a Joukowski airfoil

I am trying to plot an equation that will give me a Joukowski airfoil and am having trouble getting any results. The equation that I am using is as follows: ...
39 views

### Is it the correct syntax with TransformedDistribution?

I define a function as f[x_] := ...;which is in fact the PDF of a random variable $X$. The PDF if given by $f_X(x)$. Let $Y$ is a random variable, which is the ...
65 views

### MMA gives error when a different PDF expression is used for the same distribution

I have the following MMA code. Note that the function I declared at the very beginning is the PDF of square of a Nakagami Distributed random variable. With $m=1$ and $P=1$, $f(h)$ becomes Exponential ...
72 views

### Solving equations with change of variables is not working?

I want to express it in the form $$\text{expr=}\int_{-\infty}^{\infty}C_1\exp\left(-t^2\right)f(t)dt$$, i.e., the integrand is a bounded smooth function $f(t)$ times $\exp(-t^2)$ and the domain of ...
39 views

### Question on Poincare section example

I'm trying to make a Poincare section. On the Wolfram Documentation Center they give an example that includes the lines ...
9k views

### How do I identify the source of a “Tag times protected” error?

I have some code that looks like Table[ a = 1; b = {2, 3} c = i;, {i, 2} ] which gives an error: Set::write: Tag Times in c {2,3} is ...
81 views

### integrating with multiple indicator functions depending on each other

I need to compute the following integral with three indicator functions, $I(x)$, $I_1(x_1)$ and $I_2(x_2)$, $$\int_0^1\int_0^1I(x)\left( \ I_1(x_1)\,x_{1} + I_2(x_2)\,x_{2}-1 \right) dx_1 dx_2$$ ...
134 views

### How to get a best fit line on a scatterplot?

I know that I am supposed to call listplot inside of the show function but I can't seem to get that to work. The best I can get is this, which has the best fit line following the scatterplot. How do I ...
66 views

### Watched a Livestream with Christopher Wolfram, he used an operator that I can't find [duplicate]

I understand /., /@, /; and documentation exists in the normal way for all of those but I can find nothing on /*
53 views

### Problem with ParametricPlot with Im and Re [closed]

I have a problem, How can I plot theses functions from 0 to 2 Pi : Re(e^(iaϕ+(iϕ)^b)), Im(e^(icϕ+(iϕ)^d)) Re(e^((iϕ)^a) e^((iϕ)^b )), Im(e^(icϕ+(iϕ)^d)) Re(e^(iaϕ+(iϕ)^b)), Im(e^((iϕ)^c) e^((iϕ)^d)...
5k views

### Matrix Multiplication in context of row and column vectors

I've been looking at some matrices in Mathematica and I've noticed something very weird: They're extremely temperamental when it comes to dot products! For example, if I have the following, ...
247 views

### How to set multiple parameters to zero?

Say I have the matrix A = {{a,b,c,d,e}, {f,g,h,j,k}} and I want to set some of these to zero. I have been doing this via ...
146 views

### Defining a variable with comma (or any other separator) in its name?

How can I define Mathematica variable/function with comma in it? For example, defineL00,1 as a variable? I plan to use L00,1 ...
15 views

### Problem with PolarPlot and Table [duplicate]

If I have a set of numbers, for example grid = N[Table[n^2/2, {n, 3, 24}]] And want to plot that as circles I can either use Graphics[] and Circle[], or ...
64 views

### Can't get a numerical value for this vector operation

I have written these codes: ...
45 views

### How can I specify the plot range of a BoxWhiskerChart? [closed]

I am combining multiple BoxWhiskerCharts using GraphicsGrid. This works properly, however I want the different charts to have ...
39 views

### A natural syntax for a Query that holds

Often I have an unevaluated expression in a RuleDelayed Key-Value pair and subsequently want ...
157 views

### Is it possible to assign numbers generated in an Error-Message?

If I have a differential equation of the form ...
39 views

### Replace argument of delayed function before it evaluates [duplicate]

How should I use replace so that f[x_] := x^2 Replace[f[3], 3 -> 1] OUT = 9 evaluates to 1, instead of 9? This way, the replacement of the argument is done ...
76 views

### Mapping over function's several parameters regions [closed]

About this post: Mapping multiple parameters of a function to specific values I wonder if the parameters a and b have ranges ...
1k views

### Why is there no PositionFunction in Mathematica?

Too often I have seen the programs of inexperienced users greatly slowed by using Position in an iterative fashion, when far faster would have been to compute a ...
76 views

### Generating sequence of averages of averages of partial sums

I have been given the following code that generates the sequence of averages (of the partial sums) of Grandi's series: ...
55 views

### Syntax for Neumann/Robin condition in NDSolve [duplicate]

I can't follow the logic of how a NeumannValue term is to be incorporated into a pde to provide a BC for NDSolve. The ...
48 views

### Experiment to test Infinite monkey theorem [closed]

I need to apply this experiment: For all numbers between [0,128] let be t {set total=0 repeat this experiment n times {set start=0 choose random number [0,255] lets be R While(R!=t) {...
189 views

### Replace For with If in Mathematica way

I have this code: ...
127 views

### Syntax f[x_][y_]

Need to understand the principle of the distinction between f[x_,y_] and f[x_][y_] It seems also that z[x_, y_][a_, b_, c_][α_, β_] := a (x + y)^b + c/(α-β) ...
139 views

### Is there an internal logic behind short form symbols, such as @ (Prefix), @@ (Apply), /@ (Map), /. (ReplaceAll) [closed]

To me, function names (such as Apply and Map) seem more intuitive than their symbols (e.g. @@...
61 views

### Why doesn't Mathematica solve this non linear (fractional) ODE? [closed]

a1 = NDSolve[{y1''[x] - 0.1 y1[x]^0.25 == 0, y1'[0] == 0, y1[1] == 1}, I get the following errors - Power::infy: "Infinite expression 1/0.^0.75 encountered ...
63 views

### List of Inequalities in RegionPlot with different colors [duplicate]

Starting from the example of the Documentation: RegionPlot[{x^2 < y^3 + 1, y^2 < x^3 + 1}, {x, -2, 5}, {y, -2, 5}] Which gives a nice plot with two ...
58 views

### Substituting within a function definition that includes Simplify

I would like to define a function like myfunc[f_] := Simplify[(f/g)] where g will be substituted/replaced with the current value of g at the time of definition. ...
463 views

### What is the meaning of “/.”? [closed]

I've looked to the built-in help of Mathematica, but I still can't understand the usage of /., like in the following expression: ...
63 views

### Partial derivative of function of two variables

This question is not enlightening nor is it difficult. But some part of my notation or how I have defined my functions is messing up the D[f,x] function. ...
47 views

### Better alternative to Hold/ReleaseHold for postfix application of Monitor

Trying to Monitor a process using the postfix notation, as in Table[Pause[n/10], {n, 5}] // Monitor[#, n] & fails: the ...
123 views

### Is there a linter to help write good Mathematica code?

I don't do much real programming, but I've recently been turned on to Atom, which has linter plugins for over 50 languages to make coding easier (most drawing on pre-existing lint-like programs). In ...
45 views

### Applying multiple functions to a single column in a table

I've seen similar questions, but I'm having trouble applying solutions found there to my situation. My sorting function: ...
47 views

### Is it possible improve the code scanning beyond what SyntaxQ does? [closed]

Please, consider this package (* ::Package:: *) BeginPackage["HelloWorld"]; a::usage="A"; b::usage="B"; Begin["Private`"]; a=1; b= End[]; EndPackage[]; ...