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I have this 2x2 matrix, which is multiplied by another 2x2 matrix.
| A B| Multiplied by | X Y| Which Equals | 1 0 |
| C D| Multiplied by | Z W| Which Equals | 0 1 |

How do I go about solving X, Y, Z, and W in terms of A, B, C, and D?

Thanks for the help!

2006-10-13 06:35:28 · 2 answers · asked by debbi610g 1 in Education & Reference Homework Help

I meant to write...
[A B
C D] abcd is Maxtrix A.

[X Y
Z W] xyzw is Matrix B.

Matrix A times Matrix B equals the matrix of

[1 0
0 1] 1001.

Hope that helps.

2006-10-13 16:03:16 · update #1

2 answers

Since the answer when you multiply is the identity matrix, the matrices must be inverses of each other.

The inverse of
[ A B]
[C D]
is
( [ D -B ]
[-C A ] ) / (AD - BC)
So ...
X = D/(AD - BC)
Y = -B/(AD - BC)
Z = -C/(AD - BC)
W = A/(AD - BC)

... By the way, AD - BC is just the determinant of the first matrix.

2006-10-17 13:58:29 · answer #1 · answered by dmb 5 · 0 0

The two equations are independent of each other. Terms in equation 1, A,B, and X,Y, do not appear in the second equation as you have presented. It is a indeterminate problem.

2006-10-13 12:44:07 · answer #2 · answered by djhopscotch 1 · 0 0

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