HW06 Problem 2 Previous Problem List Next 1 point Suppose th
HW-06: Problem 2 Previous Problem List Next (1 point) Suppose that: 5-45 1-4 A= and B =| 4-1 | 4 5 -5-4-4 Given the following descriptions, determine the following elementary matrices and their inverses.
Solution
Write the augmented matrix
Make the pivot in the 1st column by dividing the 1st row by 5
Multiply the 1st row by 4
Subtract the 1st row from the 2nd row and restore it
Multiply the 1st row by -5
Subtract the 1st row from the 3rd row and restore it
Make the pivot in the 2nd column by dividing the 2nd row by 11/5
Multiply the 2nd row by -4/5
Subtract the 2nd row from the 1st row and restore it
Multiply the 2nd row by -8
Subtract the 2nd row from the 3rd row and restore it
Make the pivot in the 3rd column by dividing the 3rd row by -109/11
Multiply the 3rd row by -1/11
Subtract the 3rd row from the 1st row and restore it
Multiply the 3rd row by -15/11
Subtract the 3rd row from the 2nd row and restore it
There is the inverse matrix on the right
| A1 | A2 | A3 | A1 | A2 | A3 | |
|---|---|---|---|---|---|---|
| 1 | 5 | -4 | 5 | 1 | 0 | 0 |
| 2 | 4 | -1 | 1 | 0 | 1 | 0 |
| 3 | -5 | -4 | -4 | 0 | 0 | 1 |
