Section 4-1: Introduction to Matrices and Basic Operations

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

What is the name of each entry of a matrix?

• Row
• Element
• Dimension
• Rectangle

What is the value of element a₂₃?

• 2
• -1
• 6
• 1

How many columns are in a 5 x 4 matrix?

• 5
• 4
• 20
• 9

In Matrix R (pictured) what is the value of element R_3,2

• 8
• 9.01
• 6
• 1

What are the dimensions of this matrix?

• 2 x 3
• 3 x 2
• 6 x 1
• 1 x 6

Subtract

• 3    -8
  0   -1
• 3   -4
  8  -13
• -3   8
  0    1
• 3   -8
  -8    1

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  

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.

How many rows does the above matrix have?

• 1

• $1\times3$
  

• $3\times1$

• 3