1. Table of Contents Matrices - Inverse of a 3  3 Matrix Recall that to find an inverse of a 2  2 matrix, apply the formula... The formula for the inverse of a 3  3 matrix is not so simple. Another method is as follows.

2. Table of Contents Slide 2 Matrices - Inverse of a 3  3 Matrix (1) Write the augmented matrix, with matrix A on the left, and the identity matrix I on the right... (2) Use elementary row operations on the matrix, until the identity matrix is on the left... (3) The resulting matrix on the right is A -1...

3. Table of Contents Slide 3 Matrices - Inverse of a 3  3 Matrix Example: Let matrix A be given on the right. Find A -1. Form the augmented matrix...

4. Table of Contents Slide 4 Matrices - Inverse of a 3  3 Matrix Using elementary row operations to get the identity on the left yields... A -1 is the resulting matrix on the right.

5. Table of Contents Slide 5 Matrices - Inverse of a 3  3 Matrix In the example the elementary row operations were not shown. It takes considerable effort and attention to detail. Since the process is so long and tedious, finding inverses on the calculator is the much preferred method.

6. Table of Contents Matrices - Inverse of a 3  3 Matrix