目次 | |
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- | $3\times 3$ determinant |

- | Example |

- | Calculator |

- | Rule of Sarrus |

$3 \times 3$ determinant

Find the determinant of a 3x3 matrix,
The cofactor expansion of $A$ along the first column is

Examples

Find the determinants of the following matrices.
Enter a 3x3 matrix and press "Execute" button. Then the determinant is displayed.

$|A|$
=

Rule of Sarrus

The $3 \times 3$ determinant is
a bit more complicated than the $2 \times 2$ determinant,
so there is a visual formula to remember.
Let us draw five lines from the top left to the bottom right of a $3 \times 3$ matrix.

Thus, the determinant of a $3 \times 3$ matrix is obtained by adding the terms obtained by drawing lines from the upper left to the lower right, and subtracting the terms obtained by drawing lines from the upper right to the lower left. This visual formula is called Rule of Sarrus.