Sec 4.1 Matrices
Matrix (matrices) DEFINITION Entry or Element A rectangular array of numbers Column 1 Column 2 Column 3 Column 4 Row 1 Entry or Element DEFINITION Row 2 Row 3 Row m Dimensions: # Rows x # Columns
Example: Find the dimensions A matrix of m rows and n columns is called a matrix with dimensions m x n Example: Find the dimensions 2 x 3 3 x 3 1 x 2 2 x 1
Equal Matrices Two matrices are equal if they have the same dimensions & the corresponding entries are equivalent Algebraically…
ADDITION & SUBTRACTION of MATRICES
To add matrices, we add the corresponding elements They must have the same dimensions A + B
To subtract matrices, we subtract the corresponding elements. They must have the same dimensions
ADDITIVE INVERSE OF A MATRIX: A matrix with the same dimensions, but the entries are the exact opposite What’s the additive inverse of A ?
Scalar Multiplication: Multiply each # inside the matrix by a real #, k, outside the matrix Think of the distributive property!
Examples:
What are your QUESTIONS?
Solving a Matrix Equation Solve for x and y: Solution Step 1: Simplify
Scalar Multiplication: Write equations & solve: 6x + 8 = 26 6x = 18 x = 3 10 – 2y = 8 -2y = -2 y = 1
Properties of Matrix Operations Let A, B and C be matrices with the same dimension: Associative Property of Addition (A + B) + C = A + (B + C) Commutative Property of Addition A + B = B + A Distributive Property of Addition and Subtraction k(A + B) = kA + kB k(A – B) = kA – kB NOTE: Multiplication is not included!!!
Questions???!!!!