6.16.1 Top new questions this week

6.16.1.1 How can I find a functional square root in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227863

A functional square root of a function $g$ is another function $f$ such that $g=f\circ f$. According to that article, there is a systematic approach to finding a functional square root that involves  ... 
[equation-solving] [calculus-and-analysis]
 

asked by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 10 votes

answered by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 2 votes

6.16.1.2 The numerics of FresnelS[]

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227893

Bug introduced in 12.1 or earlier and persisting through 12.1.1 or later 
[CASE:4615361] 
Note: A worse problem existed in 12.0 for inputs greater than 8 and of precisions less than 43.66; 12.1 fixed  ... 
[bugs] [numerics] [special-functions]
 

asked by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 9 votes

answered by J. M.'s technical difficultieshttps://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 6 votes

6.16.1.3 How to enter a nuclear reaction?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227846

Sometimes the simplest things are the most difficult, I need to make a presentation, and I thought to do it in Mathematica, I wanted to do a demonstration too, well...this is the Rutherford's equation 
... 
[formatting] [physics] [writing]
 

asked by Chris Schwenke https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=65367 9 votes

answered by Bob Hanlon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9362 14 votes

6.16.1.4 How to find a numerical antiderivative with NIntegrate methods?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227869

@JimBelk asked in 
Interpolating an Antiderivative 
how to find a numerical antiderivative. 
I gave an answer that uses NDSolve with the default method for integrating 
$y'=f(x,y)$. 
However for  ... 
[calculus-and-analysis] [numerical-integration] [approximation]
 

asked by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 8 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 9 votes

6.16.1.5 How to draw one-line Venn diagram?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227990

This is the a list of set. 
data = {{"A"}, {"J"}, {"Q"}, {"G", "H"}, {"I", "O"}, 
{"B", "C", "E",  ... 
[graphics] [visualization]
 

asked by partida https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=15961 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 10 votes

6.16.1.6 How to express permutation as the least number of exchanges

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227996

If there are grammatical or terminological errors in the following description, please help correct: 
In some problems, it is necessary to find out what minimum number of exchanges can change a list  ... 
[combinatorics] [permutation]
 

asked by Ordinary users68 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 5 votes

answered by Hausdorff https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=73380 5 votes

6.16.1.7 Remove mesh triangles in contour plot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=227837

How do I get rid of the mesh in this contour plot? 
ContourPlot[x^2 + y^2, {x, -10, 10}, {y, -10, 10}, 
Contours -> {1.0, 4.0, 10.5}, ContourStyle -> None, 
ContourShading ->  ... 
[plotting]
 

asked by QuantumDot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2048 5 votes

answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 6 votes