Inverses Flashcards
0
Q
A^-1 as a product of elementary matrices
A
= Elast…Efirst
1
Q
AB = In and BA = In, when
A
B = A^-1
2
Q
A as a product of elementary matrices
A
= Efirst^-1…Elast^-1
3
Q
How to Find the Inverse of A
A
[A | In] = [In | A^-1]
- will not get identity matrix if A does not have an inverse
4
Q
A has an inverse (rank)
A
If rank(A) = n
5
Q
Inverse of a 2 x 2 matrix
A
(1/ad-bc) [d -b \ -c a]
6
Q
When A - coefficient matrix, B - answers to equations and X - solutions,
A
AX = B
