Pierre Frédéric Sarrus (10 March 1798, Saint-Affrique - 20 November 1861) was a French mathematician. Sarrus was professor at the University of Strasbourg, France (1826-1856) and member of the Academy of Sciences in Paris (1842). He discovered a mnemonic rule for solving the determinant of a 3-by-3 matrix, named Sarrus' scheme, which provides an easy-to-remember method of working out the determinant of a 3-by-3 matrix.

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% Mnemonic rule for matrix determinant% Author: Alain Matthes\documentclass[]{article}\usepackage[utf8]{inputenc}\usepackage[upright]{fourier}\usepackage{tikz}\usepackage[active,tightpage]{preview}\PreviewEnvironment{tikzpicture}\setlength\PreviewBorder{5pt}%\usetikzlibrary{matrix}\usepackage{fullpage,amsmath}\begin{document}Pierre Frédéric Sarrus (10 March 1798, Saint-Affrique - 20 November 1861) was a French mathematician.Sarrus was professor at the University of Strasbourg, France (1826-1856) and member of the Academy of Sciences in Paris (1842). He discovered a mnemonic rule for solving the determinant of a 3-by-3 matrix, named Sarrus' scheme, which provides an easy-to-remember method of working out the determinant of a 3-by-3 matrix (as illustrated below)\tikzset{node style ge/.style={circle}}det(M)=$\left|\begin{matrix}a_{11} & a_{12} & a_{13} \\a_{21} & a_{22} & a_{23} \\a_{31} & a_{32} & a_{33} \\\end{matrix}%\right|$=$\big(a_{11}a_{22}a_{33}+a_{21}a_{32}a_{13}+a_{31}a_{12}a_{33}\big)-\big(a_{13}a_{22}a_{31}+a_{23}a_{32}a_{11}+a_{33}a_{12}a_{31}\big)$\begin{tikzpicture}[baseline=(A.center)]\tikzset{BarreStyle/.style = {opacity=.4,line width=4 mm,line cap=round,color=#1}}\tikzset{SignePlus/.style = {above left,,opacity=1,circle,fill=#1!50}}\tikzset{SigneMoins/.style = {below left,,opacity=1,circle,fill=#1!50}}% les matrices\matrix (A) [matrix of math nodes, nodes = {node style ge},,column sep=0 mm]{ a_{11} & a_{12} & a_{13} \\a_{21} & a_{22} & a_{23} \\a_{31} & a_{32} & a_{33} \\a_{11} & a_{12} & a_{13} \\a_{21} & a_{22} & a_{13}\\
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