Matrices

Question 1

What is the determinant of a 2x2 matrix?

Answer 1

ad - bc

Question 2

How do you find the determinant of a 3x3 matrix?

Answer 2

Strike the first row and column, and multiply the determinant of the remainder by a.

Strike the top row and middle column, multiple determinant of reminder by b, and subtract this.

Strike the top row and third column, multiply the determinant of the remainder by c, and add this.

Question 3

If a matrix is singular, what is its determinant?

Answer 3

0

Question 4

What property does a singular matrix have?

Answer 4

It has no inverse, as 1/detM is undefined.

Question 5

What is the inverse of a 2x2 matrix?

Answer 5

1/detM (d -b -c a)

Question 6

What the steps of finding the inverse of a 3x3 matrix?

Answer 6

Find det A

Form matrix of minors

Form a matrix of cofactors (leaving + and flipping - )

Transpose matrix (flip rows and columns)

Inverse = 1/detA x transposed matrix