9.13.1 Top new questions this week

9.13.1.1 Arithmetic progression in LaTeX

https://tex.stackexchange.com/landing/r/digest?cta=question&id=676605

How the following image could be generated in LaTeX? It is an arithmetic progression. 
I don't have any idea how to do it. Can you help me? 
\documentclass[a4paper, 11pt]{article} 
\begin{document} 
$$\... 
[tikz-pgf]
 

asked by ludrzgszwptfpzmqfj_bbitf_com https://tex.stackexchange.com/landing/r/digest?cta=user&id=290955 Score of 11

answered by Mico https://tex.stackexchange.com/landing/r/digest?cta=user&id=5001 Score of 11

9.13.1.2 How to draw a 3D sphere and a 3D cone for Spherical coordinates

https://tex.stackexchange.com/landing/r/digest?cta=question&id=676181

I'm trying to replicate this figure: 
Right know, I have this code: 
\begin{figure}[H] 
\centering 
\begin{tikzpicture}[yzx, scale = 0.9] 
\draw[->] (0,0,0) -- (5.5,0,0) node(x)[left]{$... 
[tikz-pgf] [tikz-trees] [3d] [tikz-3dplot] [tikz-3d]
 

asked by Peluche https://tex.stackexchange.com/landing/r/digest?cta=user&id=262923 Score of 8

answered by Juan CastaA~+-o https://tex.stackexchange.com/landing/r/digest?cta=user&id=231368 Score of 12

9.13.1.3 Tikz: How to make the arrow bend along the curve in decoration?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=676380

When I'm drawing a contour, I want to know how to make the arrow bend along the curve in decoration. Please see the example below. 
Here is my MWE: 
\documentclass{standalone} 
\usepackage{tikz} 
\... 
[tikz-pgf] [tikz-arrows] [tikz-decorations]
 

asked by Huanyu Shi https://tex.stackexchange.com/landing/r/digest?cta=user&id=269456 Score of 7

answered by Thruston https://tex.stackexchange.com/landing/r/digest?cta=user&id=15036 Score of 5

9.13.1.4 How can I make a loop to draw a sequence of projections on two lines?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=676672

I want to draw this problem: Given distinct straight lines $O A$ and $O B$. From a point in $O B$ a perpendicular is drawn to $O A$; from the foot of this perpendicular a line is drawn perpendicular ... 
[tikz-pgf] [loops]
 

asked by John Paul Peter https://tex.stackexchange.com/landing/r/digest?cta=user&id=250010 Score of 6

answered by Qrrbrbirlbel https://tex.stackexchange.com/landing/r/digest?cta=user&id=16595 Score of 9

9.13.1.5 Ordinal numbers in chapter number

https://tex.stackexchange.com/landing/r/digest?cta=question&id=676654

I'm working on a daily journal and I want every \chapter number to contain an ordinal indicator (st, nd, rd etc.). See attached picture as an example (I marked in red what I'm looking for). Is there a ... 
[sectioning] [numbering]
 

asked by falkbooks1222 https://tex.stackexchange.com/landing/r/digest?cta=user&id=287827 Score of 6

answered by Mico https://tex.stackexchange.com/landing/r/digest?cta=user&id=5001 Score of 9

9.13.1.6 Draw a circle with all possible squares within it

https://tex.stackexchange.com/landing/r/digest?cta=question&id=676523

How to draw a circle with radius r where you insert all possible squares of width s in it? Each square is allowed to cross the periphery at the corner/corners of the square if possible. The squares ... 
[tikz-pgf] [circles]
 

asked by UnknownW https://tex.stackexchange.com/landing/r/digest?cta=user&id=50564 Score of 6

answered by Qrrbrbirlbel https://tex.stackexchange.com/landing/r/digest?cta=user&id=16595 Score of 8

9.13.1.7 How to define \sc in TeX?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=676277

Taking inspiration from the TeXbook (page 350) I defined: 
\font\tensc=eccc1000 
\font\twelvesc=eccc1200 
For example, the following works as expected: 
\font\tensc=eccc1000 
\centerline{Donald {\tensc ... 
[fonts] [plain-tex] [small-caps]
 

asked by user989070 https://tex.stackexchange.com/landing/r/digest?cta=user&id=290775 Score of 6

answered by egreg https://tex.stackexchange.com/landing/r/digest?cta=user&id=4427 Score of 7