Matrices I Can Use matrices to solve problems
Matrices
I Can… • Use matrices to solve problems (3. 01) • Use matrices to display and interpret data (3. 02)
Matrix – a rectangular arrangement of numbers Ex:
Describing Matrices =2 x 3 matrix =3 x 2 matrix =3 x 1 matrix =1 x 1 matrix What is the rule for describing matrices?
Dimensions – the number of rows by the number of columns a matrix has. *Matrices are described by their dimensions Rows (across) x Columns (up and down) =2 x 2 matrix =3 x 1 matrix
Element – each entry within a matrix • Each element is defined by its position in the matrix. • In a matrix A, an element in row i and column j is represented by aij
• We name matrices using a capitol letter • Each element will be named using the same letter only lower case
Example: A= a 11 (read as ‘a one ’)= 2 (first row, first column) a 23 (read as ‘a two three') = 9 (second row, third column) a 13 = 5 a 21 = a 22 = a 12 =
If: + + = = = No Solution What is the rule for adding and subtracting matrices?
Adding and Subtracting Matrices • The dimensions must be exactly the same • You add or subtract the corresponding elements
Scalar Multiplication Scalar – a constant (number by itself) ex: 5, -8, 14 • You multiply each element by the scalar ex: -2 =
You try…. 1. 4 2. -7 3. 10 = = =
1. 2. 3.
Creating Matrices • Data that is organized in columns and rows can be written has a matrix. Create a matrix for the following information: Gender Brown Eyes Blue Eyes Green Eyes Gray Eyes Male 9 3 1 0 Female 11 4 3 1
9 3 1 0 11 4 3 1
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