Module 9: Matrices

What is a Matrix?

• An equation of over 5 numbers or symbols 
• A set of numbers in rows and columns
• A method of finding the n^th value of a series
• A complicated number system

In Matrix R (pictured) what element is in the second row, third column?

• 8
• 9.01
• 6
• 1

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.

What is the name of each entry of a matrix?

• Row
• Element
• Dimension
• Rectangle

What comes first in the order?

• Row
• Column

Dimensions?

• a
• b
• c
• d

Multiply

• 20     15    -10
  30     -5         0
• -20      15     -10
  30     -5          0
• 1        8       3
  11     4        5
• 20     -15     10
  -30         5        0  

Multiply

• 25
  25
  5
• -25
  25
  -5
• -10
  -10
  -6
• 10
  10
  6

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 are the dimensions of this matrix?

• 2 x 3
• 3 x 2
• 6 x 1
• 1 x 6