6: Matrices Flashcards
1
Q
What is the determinant of a 2x2 matrix?
A
ad-bc
2
Q
What is the inverse of a 2x2 matrix?
A
1/det(M) * (d -b)
(-c a)
3
Q
(AB)^-1 is equal to what?
A
A^-1*B^-1
4
Q
What are the steps to find the determinant of a 3x3 matrix?
A
- Find detA
- Form the matrix of minors(M)
- Form the matrix of cofactors(C)
- Find the transpose(C^T)
- The inverse is 1/detA * C^T
5
Q
How to tell if a matrix is singular?
A
If detM = 0
6
Q
How to tell if a system of linear equations is consistent?
A
If there is at least one set of values that satisfies all of the equations simultaneously.
