All About Matrices What is a Matrix Any

All About Matrices

What is a Matrix? Any rectangular array of numbers in rows and columns, usually surrounded by square brackets. The size or dimension is important. The contents of the matrix are called its elements. Brackets

Properties of Matrices • The number of rows is always reported before the number of columns. • Rows go across Columns go up and down [] 24 69 53 Dimension: This is a 3 x 2 matrix Because you have 3 rows and 2 columns Element (1, 2) = 4 Element(3, 2) = 3

This matrice has 2 rows and 3 columns. The dimension of this matrice is (2 x 3)

Examples Give the dimensions of the following matrices 1. ) 2. )

Examples [ ][ ] 456 234 16 -4 12 6 12 – 3 8 4 3 4 8 8 2 4 4 6

Examples Construct a (2 x 4) matrice that has an element 1. ) at (2, 3) = 0 2. ) Construct a (2 x 1) matrice that has an element at (2, 1) = -3

Examples 1. ) 2. )

Discover the Math – page 52 Thomas’s Report for November Sales T S white T = T-shirts S = sweatshirts black What does element (1, 1) represent? Row 1, Column 1 What does element (2, 2) represent? Row 2, Column 2

Discover the Math – page 52 Thomas’s Report for December Sales t s white T = T-shirts S = sweatshirts black What does element (1, 1) represent? What does element (2, 2) represent?

Discover the Math – page 52 Thomas’s Report for Nov/Dec Sales t s white T = T-shirts S = sweatshirts black Dimensions are (2 x 2)

Discover the Math – page 52 Thomas’s Report for November Sales t s white T = T-shirts S = sweatshirts black What does element (1, 1) represent? What does element (2, 2) represent?

Adding & Subtracting Matrices • You can only add two matrices if they have the same dimension. + = =

Adding & Subtracting Matrices + =

YOU CANNOT ADD/SUBTRACT MATRICES WITH DIFFERENT DIMENSIONS. + (2 x 3) = (3 x 1) Not Possible

(Scalar) x (Matrice) = 3 x 2 x =

Assignment • Page 56 – Communicate the Key Ideas 1, 3, 4 - Page 56 1, 2, 3, 4, 5, 6