9.31.1 Top new questions this week

9.31.1.1 How do I write LaTeX code for matrices of this form?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=684958

I want to write code for a matrix of the form given in the picture below. How can I do it? 
What I have tried is the following code: 
\begin{bmatrix} 
a &      r &      0 & \dots \\ 
... 
[math-mode] [matrices]
 

asked by Mr.Gandalf Sauron https://tex.stackexchange.com/landing/r/digest?cta=user&id=296477 Score of 12

answered by Mico https://tex.stackexchange.com/landing/r/digest?cta=user&id=5001 Score of 13

9.31.1.2 Replicate a diagram using TikZ

https://tex.stackexchange.com/landing/r/digest?cta=question&id=685282

I want to replicate the attached diagram. I did it using simple TikZ. 
I got stuck on a single thick curved line shown on the attached diagram. I need to do the following: 
Draw the curved line. 
... 
[tikz-pgf] [diagrams]
 

asked by OOzy Pal https://tex.stackexchange.com/landing/r/digest?cta=user&id=23436 Score of 9

answered by Terrarium https://tex.stackexchange.com/landing/r/digest?cta=user&id=206257 Score of 8

9.31.1.3 Drawing recursive polygons in Tikz

https://tex.stackexchange.com/landing/r/digest?cta=question&id=685076

To draw different kinds of polygons (with different rotations, scaling factors,...etc.), I use the following code (producing the top picture) modified from 
this answer to this post. The original code ... 
[tikz-pgf]
 

asked by Hany https://tex.stackexchange.com/landing/r/digest?cta=user&id=93617 Score of 8

answered by Qrrbrbirlbel https://tex.stackexchange.com/landing/r/digest?cta=user&id=16595 Score of 13

9.31.1.4 I use color with left color, right color and fill in tikz, but why are these two cases differenti"\274\237

https://tex.stackexchange.com/landing/r/digest?cta=question&id=684932

\begin{tikzpicture} 
\draw[left color=BlueGreen,right color=BlueGreen] (0,0) rectangle (2,1); 
\end{tikzpicture} 
\begin{tikzpicture} 
\draw[fill=BlueGreen] (0,0) rectangle (2,1); 
\end{tikzpicture} 
The ... 
[tikz-pgf]
 

asked by robot https://tex.stackexchange.com/landing/r/digest?cta=user&id=296460 Score of 8

answered by Ulrike Fischer https://tex.stackexchange.com/landing/r/digest?cta=user&id=2388 Score of 9

9.31.1.5 Nicer way to cancel whole fraction

https://tex.stackexchange.com/landing/r/digest?cta=question&id=685276

I attempted to utilize \cancel{} to strike through entire fractions. While it functions okay for fractions that occupy a small space, it appears slightly awkward for larger fractions. The angle of the ... 
[fractions] [strikeout]
 

asked by Terrarium https://tex.stackexchange.com/landing/r/digest?cta=user&id=206257 Score of 7

answered by samcarter_is_at_topanswers.xyz https://tex.stackexchange.com/landing/r/digest?cta=user&id=36296 Score of 4

9.31.1.6 Creating various road symbols with TikZ

https://tex.stackexchange.com/landing/r/digest?cta=question&id=684899

I am trying to create three road symbols with TikZ. These are 
US Interstate Shield 
US Highway Shield 
Generic State Highway "pill". This is basically a rectangle capped with two semi-... 
[tikz-pgf]
 

asked by Logan https://tex.stackexchange.com/landing/r/digest?cta=user&id=270870 Score of 7

answered by Juan CastaA~+-o https://tex.stackexchange.com/landing/r/digest?cta=user&id=231368 Score of 10

9.31.1.7 How to correct spacing between `=` under the SUM sign when using breqn package?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=684816

In this MWE 
\documentclass[12pt]{book} 
\usepackage{amsmath} 
\usepackage{breqn} 
\newcommand{\myEquation}{\sum_{n=0}^{\infty} x^{n +5} a_{n} = \sum_{n=5}^{\infty}a_{n -5} x^{n} } 
\begin{document} 
\... 
[spacing] [typography] [breqn]
 

asked by Nasser https://tex.stackexchange.com/landing/r/digest?cta=user&id=14594 Score of 7

answered by egreg https://tex.stackexchange.com/landing/r/digest?cta=user&id=4427 Score of 3