RuleOfSarrus.md (650B)
1 # Rule of Sarrus 2 3 Khan U2 4 5 **Definition:** The rule of Sarrus is a shortcut for finding the determinant of a 3x3 matrix. 6 7 Formula: 8 9 [a b c] 10 Det ([d e f]) = aei + bfg + cdh - afh - bdi - ceg 11 [g h i] 12 13 When looking at the matrix we add the multiplied diagonals (starting from top row 3 values) to the right and subtract the diagonals to the left (multiplying each value in the diagonal). 14 15 See [Determinant](Determinant.md) for calculating determinants, what they represent, and how to find 2x2 with a formula. 16 17 Ex: 18 19 [1 2 4] 20 A = [2 1 3] 21 [3 4 8] 22 23 Det(A) = 1x1x8 + 2x3x3 + 4x2x4 - 1x3x4 - 2x2x8 - 4x1x3 24 25 = 8 + 18 + 32 - 12 - 32 - 12 26 27 = 2