Rule of Sarrus
![Sarrus' rule: The determinant of the three columns on the left is the sum of the products along the solid diagonals minus the sum of the products along the dashed diagonals](/Images/godic/202502/09/Sarrus_rule.svg2131.png")
![Alternative vertical arrangement](/Images/godic/202502/09/Sarrus_rule_vertical.svg2131.png")
Sarrus' rule or Sarrus' scheme is a method and a memorization scheme to compute the determinant of a 3×3 matrix. It is named after the French mathematician Pierre Frédéric Sarrus.
Consider a 3×3 matrix
then its determinant can be computed by the following scheme: