Inverse and Determinants of Matrices

What size is this matrix?

• 2x2

• 2x3

• 3x2

• 1x6

Dimensions?

• a
• b
• c
• d

What must be true in order to ADD two matrices?

• They must be square.
• The dimensions must be equal.
• The determinant can't equal 0.
• The column of the 1st must equal the row of the 2nd.

Find A+B

• 8     10
  8      1 
• 12     25
  7     1
• 10     30
  0     1
• can't add two together because the rows dont match columns

What would be the dimensions (output) of AB?

• undefined

• 2 X 2

• 3 X 2

• 3 X 3

find: B*A

• 47     30
  9     5
• 17     15
  42     35
• 10     25
  7     1
• not possible because rows do not match columns

What is the determinant of this matrix?

• -2

• 2

• 10

• 24

What is the determinant of this matrix?

• 5

• -5

• 0

• -12

What is the formula for the determinant of a 2x2 matrix?

• ad-bc

• ab-cd

• ad+bc

• (a+d)(b+c)

Calculate the determinant

• 0
• -15
• -70
• 10