%%
%% A DANTE-Edition example
%%
%% Example 36-00-17 on page 775.
%%
%% Copyright (C) 2011 Herbert Voss
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%%
%% See
http://www.latex-project.org/lppl.txt for details.
%%
%%
%% ====
% Show page(s) 1
%%
\documentclass[]{article}
\pagestyle{empty}
\setlength\textwidth{201.70511pt}
\setlength\parindent{0pt}
\usepackage{pst-node,multido,amsmath}\newdimen\xMax
\newdimen\yMax
\newcount\xLines
\newcount\yLines
\newdimen\dx
\newdimen\dy
\definecolor{lightred}{rgb}{1.0, 0.8, 0.8}
\makeatletter
\newcommand\grid[3][black]{{%
\psset{linewidth=0.1pt}
\xMax=#3%
\yMax=#2%
\dx=5mm \xLines=\xMax \divide\xLines by \dx%
\dy=5mm \yLines=\yMax \divide\yLines by \dy%
\advance\xLines by 1%
\advance\yLines by 1%
\yMax=\dy \multiply\yMax by \yLines%
\xMax=\dx \multiply\xMax by \xLines%
\advance\xLines by 1%
\advance\yLines by 1%
\psset{unit=1pt, linecolor=#1}%
\multido{\rA=0+\strip@pt\dx}{\xLines}{\psline(\rA,0)(\rA,\yMax)}%
\multido{\rA=0+\strip@pt\dy}{\yLines}{\psline(0,\rA)(\xMax,\rA)}%
}}
\makeatother
\newsavebox{\gridbox}
\newenvironment{dogrid}[1][\linewidth]{%
\begin{lrbox}{\gridbox}%
\begin{minipage}{#1}%
}{%
\end{minipage}%
\end{lrbox}%
\yMax=\dp\gridbox \advance\yMax by \ht\gridbox
\noindent%
\raisebox{-1.05\dp\gridbox}{\grid[lightred]{\yMax}{\wd\gridbox}}%
\usebox{\gridbox}
\vspace{0.5cm}
}
\begin{document}
\begin{dogrid}
\[
\begin{array}{rcll}
y & = & x^{2}+bx+c\\
& = & x^{2}+2\cdot{\displaystyle\frac{b}{2}x+c}\\
& = & \underbrace{x^{2}+2\cdot\frac{b}{2}x+
\left(\frac{b}{2}\right)^{2}}-{\displaystyle \left(\frac{b}{2}\right)^{2}+c}\\
& & \qquad\color{blue}\left(x+{\displaystyle \frac{b}{2}}\right)^{2}\\
& = & {\color{blue}\left(x+{\displaystyle \frac{b}{2}}\right)^{2}}
\color{red}-\left({\displaystyle \frac{b}{2}}\right)^{2}+c & \left|+\left({\displaystyle \frac{b}{2}}\right)^{2}-c\right.\\
y+\left({\displaystyle \frac{b}{2}}\right)^{2}-c & = & \left(x+{\displaystyle \frac{b}{2}}\right)^{2} & \left|(\textrm{Scheitelpunktform})\right.\\
y-y_{S} & = & (x-x_{S})^{2}\\
\mbox{\textbf{S}}\mathbf{\left(x_{S};y_{S}\right)} & \,\textrm{bzw.}\, &
\mbox{\textbf{S}}\mathbf{\left(-{\displaystyle \frac{b}{2};\,
\left({\displaystyle \frac{b}{2}}\right)^{2}-c}\right)}
\end{array}
\]
\end{dogrid}
\end{document}
