2.5 The Gauss-Jordan Method for Calculating Inverses

Finding Inverses• When the matrix is a 2 x 2,

the inverse is easy to find using the determinant.

• What if the inverse of a larger square matrix needs to be found?

• That is when G-J needs to be performed with the original matrix and Identity matrix side by side.

How this works…• You set up the process to

look like:

• Then do row manipulations until it looks like:

• What is the inverse of an inverse matrix?

A I

1I A

11A A

Find the Inverse12 1

1 3A

Find the Inverse

6 2

2 1A

Find the Inverse

4 2 3

8 3 5

7 2 4

A

Find the Inverse

2 2 0

0 2 0

3 0 1

A

2.5 The Gauss-Jordan Method for Calculating Inverses

• Problems to complete:Pg. 101 #1, 3, 4, 7