How do I find the determinant of a #3xx3# matrix?

1 Answer
Sep 7, 2015


Use co-factor expansion along any row or column of your choice.
If a row or column contains a zero entry, then it is time-efficient to use that row or column


Recall that by co-factor expansion we mean adding all the entries in a particular row or column 1 at a time, multiplied by the co-factor multiplied by the minor of the entry #(-1)^(i+j)M_(ij)#
The minor is the 2x2 determinant that remains when you delete row I and column j, and it is found in normal methods.

Let me show an example - attached :

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