[texhax] questions about ams environments

[Germain BOYER]

Bonjour , 

Look a this tex file. There is questions in the tex file. 
I you have answer to the questions please send me this answers by mail.
Thanks.



\documentclass[10pt]{article} 

\usepackage[latin1]{inputenc} 

\usepackage[T1]{fontenc} 

\usepackage{calc} 

% \usepackage[fleqn]{amsmath} 

\usepackage{amsmath} 

\usepackage{amsfonts,amssymb} 

\usepackage{mathtools} 

%---------------------------------------------------------------------------------------------------------------------------- 
\usepackage{geometry} 
\geometry{nohead,nofoot} 
\geometry{a4paper,dvips} 
\geometry{portrait} 
\geometry{left=2cm,right=2cm,top=2cm,bottom=2cm} 
%---------------------------------------------------------------------------------------------------------------------------- 

\usepackage[frenchb]{babel}  
\frenchbsetup{StandardLists=true} 

\begin{document} 
%\abs{ \frac{4}{5} }   
% the documentation of mathtools talks about \abs and \norm but it doesn't work 
% \norm{ \dfrac{4}{5} \vect{AB} } 
% 
\noindent  
10 \\ 
 $\begin{alignedat}{1} 
10^1 &= 1 + 9 = 1 + 3\times 3=1+3k_1 \\ 
10^2 &= 1 + 99 = 1 + 3\times 33=1+3k_2 \\ 
10^3 &= 1 + 999 = 1 + 3\times 333=1+3k_3  
\end{alignedat}$ \\ 
  \\ \\ 
%\hspace*{-5pt}  
% 
% 
% I write \hspace*{-5pt} because the following line was not in the left margin. 
% Is it possible to do this for example by a setlength like \setlength{\tabcolsep}{0mm} or by other mean ? 
% 
% 
$\begin{alignedat}{3} 
10^1 &= 1 + 9     & \quad 10^1 &= 1 + 9      &   \quad & \text{line 01} \\ 
10^2 &= 1 + 99   & \quad 10^2 &= 1 + 99    &    \quad & \text{line 02} \\ 
10^3 &= 1 + 999 & \quad 10^3 &= 1 + 999   &    \quad & \text{line 03} \\ 
\end{alignedat}$ \\ 
%\hspace*{-5pt}  
% 
% 
% I write \hspace*{-5pt} because the following line was not in the left margin. 
% Sorry for my bad english. I hope you understand what i mean. 
% Is it possible to do this for example by a setlength like \setlength{\tabcolsep}{0mm} or by other mean ? 
% 
% 
$\begin{alignedat}{1} 
10^1 &= 1 + 9 = 1 + 3\times 3=1+3k_1 \\ 
10^2 &= 1 + 99 = 1 + 3\times 33=1+3k_2 \\ 
10^3 &= 1 + 999 = 1 + 3\times 333=1+3k_3  
\end{alignedat}$ \\ 
% 
% 
% A solution is in the following lines but it's not a regular solution. 
% For one block i can use flalign but the width of the block is \textwidth so parbox is better. 
%  
% 
\parbox{\widthof{$10^3 = 1 + 999 = 1 + 3\times 333=1+3k_3$}}{\begin{align*} 
10^1 &= 1 + 9 = 1 + 3\times 3=1+3k_1 \\ 
10^2 &= 1 + 99 = 1 + 3\times 33=1+3k_2 \\ 
10^3 &= 1 + 999 = 1 + 3\times 333=1+3k_3  
\end{align*} } \\ 
% 
% 
% There is a space before the following line. 
% Is it possible to control this space by a setlength like \setlength{\tabcolsep}{0mm} or by other mean ? 
% It' possible to write \\[-1.5\baselineskip] after begin of flalign but it's not a regular solution. 
% 
%  
\begin{flalign*}  
10^1 &= 1 + 9 = 1 + 3\times 3=1+3k_1 & \\ 
10^2 &= 1 + 99 = 1 + 3\times 33=1+3k_2  \\ 
10^3 &= 1 + 999 = 1 + 3\times 333=1+3k_3  
\end{flalign*} 
% 
% 
% There is a space before the following line. 
% Is it possible to control this space by a setlength like \setlength{\tabcolsep}{0mm} or by other mean ? 
% It' possible to write \\[-1.5\baselineskip] after begin of flalign but it's not a regular solution 
% 
%  
\begin{alignat*}{2} 
x& = y_1-y_2+y_3-y_5+y_8-\dots 
                  &\quad& \text{by \eqref{eq:C}}\\ 
 & = y'\circ y^*  && \text{by \eqref{eq:D}}\\ 
 & = y(0) y'      && \text {by Axiom 1.} 
\end{alignat*}  
% 
% 
% of course two spaces : one for \end{alignat*} and one for \begin{align} 
% Is it possible to control this 
% 
% 
\begin{align*} 
x& = y_1-y_2+y_3-y_5+y_8-\dots 
                  &\quad& \text{by \eqref{eq:C}}\\ 
 & = y'\circ y^*  && \text{by \eqref{eq:D}}\\ 
 & = y(0) y'      && \text {by Axiom 1.} 
\end{align*} 
\end{document}  
  
  
  
Germain BOYER, germain.boyer at ac-toulouse.fr 21-09-2009