1. Ch.8.6_MatrixMultiplication.notebook March 05, 2012
Chapter 8.6
Matrix Multiplication
Before multiplying matrices, you need
to check the dimensions of each matrix
rows x columns
The number of COLUMNS of the first matrix
needs to match the number of ROWS of the
second matrix
rows x columns
A2x3B3x2
2x3 3x2
The solution matrix will have the # of ROWS from
the first matrix and the # of COLUMNS from the
second matrix
2x3 3x2
Solution matrix will be 2x2
To multiply, we use row­by­column multiplication
Multiply corresponding elements and add the
products
(2)(1) + (1)(0) + (3)(6)
21
AB = Row 1 Column 1 Row 1 Column 2
Row 2 Column 1 Row 2 Column 2

2. Ch.8.6_MatrixMultiplication.notebook March 05, 2012
Find BA

3. Ch.8.6_MatrixMultiplication.notebook March 05, 2012