Determinant of a 3x3 matrix

Last updated: Jan. 2nd, 2019
  Find the determinant of a 3x3 matrix,
3x3 matrix
, by using the cofactor expansion.

  Explanation

  The cofactor expansion of $A$ along the first column is

  Calculating the 2x2 determinant in each term,
From these, we obtain
3x3 determinant
Example:
  The determinant of
3x3 determinant example
is
3x3 determinant calculation example
Calculator
  Enter a 3x3 matrix and press "Execute" button. Then the determinant is displayed.
123
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$|A|$ =