# How do you find the determinant of #((1, 2, 1), (0, 4, 3), (1, 2, 2))#?

##### 2 Answers

Mar 11, 2016

#### Explanation:

Mar 11, 2016

Use alternative method to find determinant is

#### Explanation:

Use two properties of determinants:

- The determinant of a matrix is unchanged by adding any multiple of a row to another row.
- The determinant of an upper triangular matrix is the product of the diagonal.

Given:

#((1, 2, 1), (0, 4, 3), (1, 2, 2))#

Subtract the first row from the third (i.e. add

#((1, 2, 1), (0, 4, 3), (0, 0, 1))#

The determinant of this upper triangular matrix is the product of the diagonal:

#1 xx 4 xx 1 = 4#