3.7.2 Greatest hits from previous weeks

Greatest hits from previous weeks:

3.7.2.1 How to typeset subscript in usual text mode?

http://tex.stackexchange.com/questions/1013/how-to-typeset-subscript-in-usual-text-mode

It's easy to make subscripts in math mode: $a_i$. 
How do I make a subscript outside math environment, likethis?
 

- asked by Pavel Shved (156 votes), answered by Stefan Kottwitz (103 votes)

3.7.2.2 How to write an ma^..\211n matrix in LaTeX?

http://tex.stackexchange.com/questions/69997/how-to-write-an-m%e2%a8%89n-matrix-in-latex

I tried using the below code but it works only for 2a^..\2112 matrix. 
\[ 
M= 
\left[ {\begin{array}{cc} 
1 & 2 \       3 & 4 \      \end{array} } \right] 
\] 
Now the following doesn't work  ...
 

- asked by Vutukuri (18 votes), answered by David (19 votes)