7.8.1 Top new questions this week

7.8.1.1 Mathematica 12.1: Don't use Accumulate or Differences on Around objects!
7.8.1.2 How to enter a repeating decimal in Mathematica
7.8.1.3 How to judge whether two groups of sequences are equal in cycles?
7.8.1.4 Simplify 1+Sqrt[2]I-Complex[1,Sqrt[2]]
7.8.1.5 How to correctly calculate the number of seating plans for the 4-couples problem?
7.8.1.6 How to approximate $PV\int_0^\infty \frac \tan x  x \text d x?$
7.8.1.7 Mirror image of graph
7.8.1.1 Mathematica 12.1: Don't use Accumulate or Differences on Around objects!

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=240449

SUMMARY: 
If a  List ,  TimeSeries , etc. of  Around  objects contains any identical elements, <... 
[error-propagation] [around] [accumulation]
 
asked by Aaron Eiben https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72186 14 votes
answered by Sjoerd Smit https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=43522 11 votes
7.8.1.2 How to enter a repeating decimal in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=240596

I don't understand how to manipulate numbers with repeating decimal in Wolfram Mathematica language. 
For example  0.3...  does not work as input and I don't see how ... 
[number-representation] [arithmetic] [number-form]
 
asked by Simpleton Jack https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22399 9 votes
answered by J. M.'s ennui https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 11 votes
7.8.1.3 How to judge whether two groups of sequences are equal in cycles?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=240325

There's a set of arrays that I want to remove repeated elements that are equal after rotation: 
... 
[list-manipulation] [filtering]
 
asked by A little mouse on the pampashttps://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 9 votes
answered by Carl Woll https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=45431 11 votes
7.8.1.4 Simplify 1+Sqrt[2]I-Complex[1,Sqrt[2]]

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=240522

The expression  1+Sqrt[2]I-Complex[1,Sqrt[2]]  should be zero. In fact,  N[1+Sqrt[2]I-Complex[1,Sqrt[2]]]  yields ... 
[simplifying-expressions] [complex]
 
asked by pdmclean https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9154 7 votes
answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 10 votes
7.8.1.5 How to correctly calculate the number of seating plans for the 4-couples problem?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=240357

Four couples a are sitting around a round table, in which husband and wife can not be adjacent. How many different seating plans are there? 
I want to get as many simple calculations as possible. 
... 
[combinatorics]
 
asked by A little mouse on the pampashttps://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 7 votes
answered by Beny Izd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=77079 8 votes
7.8.1.6 How to approximate $PV\int_0^\infty \frac \tan x  x \text d x?$

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=240461

What's the mathematica command to get the numerical value of  : 
$$PV\int_0^\infty \frac{\tan x}{x}\text{d}x?$$ 
where $PV$ is the principal value. 
[numerical-integration] [approximation]
 
asked by Ali Shadhar https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=67714 7 votes
answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 7 votes
7.8.1.7 Mirror image of graph

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=240571

I need to display a directed acyclic graph (say Hasse diagram of partial order) oriented with minimal elements at the bottom, maximal elements at the top as is conventional for Hasse diagrams. 
I tried ... 
[graphs-and-networks]
 
asked by Mike https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=62210 6 votes
answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes