%% %% Ein Beispiel der DANTE-Edition %% Mathematiksatz mit LaTeX %% 3. Auflage %% Beispiel A-02-1 auf Seite 402. %% Copyright (C) 2018 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[10pt]{exaarticle} \pagestyle{empty} \setlength\textwidth{352.81416pt} \AtBeginDocument{\setlength\parindent{0pt}} %StartShownPreambleCommands \usepackage{axessibility} \usepackage{libertine} %StopShownPreambleCommands \begin{document} The golden mean is the number $\frac{1 + \sqrt{5}}{2},$ that is the root larger in modulus of $$x^2 - x - 1.$$ It is usually defined as the ratio of two lengths $$a$$ and $$b$$ such that \begin{equation*} (a+b) : a = a : b. \end{equation*} Let $$x$$ be the ratio $$\frac{a}{b}$$, we have $$\frac{a+b}{a} = 1 + \frac{1}{x}$$, from which we get the equation $$x^2 = x + 1$$. \end{document}