Introduction To Matrices Chapter 4.1 Introduction To Matrices

Def: A matrix is a rectangular array of elements in rows and columns Notation: [ ] For example Row Column Def: Each number in a matrix is called an element.

Notation: A matrix with 8 rows and 5 columns is a 8 x 5 matrix C8x5 1. Find the element in row 6 column 4

2. How many rows and columns does matrix R have? R3x2 3. What are the dimensions of matrix A? A =

“The element in matrix A in the 2nd row and 3rd column” 4.) Find: A23 “The element in matrix A in the 2nd row and 3rd column” In a matrix, information is designated by its address A = Read as:

5. You can multiply a matrix by a number (scalar multiplication) Def: Two matrices are equal if they have the same dimensions and if each element of one matrix is equal to the corresponding element of the other.

6. Are these matrices equal? and Not equal Same elements but not the same dimensions 2x3 3x2 7. Are these matrices equal? Equal Elements are equal and the same dimensions and 2x2 2x2

Solve by setting them equal You can use the fact that corresponding elements are equal to solve a matrix equation 8. Solve by setting them equal Both 2x1 matrices

9. solve Both 2x1 matrices

10.) A triangle has the following vertices: Vertex (A) (B) (C) A (2, 3) B (-3, -3) C (1, -4) x • 2 = y Enlarge ABC so its perimeter Is twice the original length

10.) (cont.) •2 =

Homework Page 191 Problems: 13-24, and 28