1. Lesson 2: Multiplying Matrices
Accel Precalc
Unit 3: Matrices
Lesson 2: Multiplying Matrices
EQ: How do you multiply matrices?

2. Condition Necessary to Multiply two Matrices:
Since each matrix represents an array of data, rules for multiplying them together depends on the position of each entry.
Condition Necessary to
Multiply two Matrices:
# of columns of 1st matrix = # of rows of 2nd matrix

3. AB will result in a 3 x 2 matrix.
Given matrix A and matrix B with the following dimensions:
AB will result in a 3 x 2 matrix.

6. Ex. 1
Matrix D is a __ by __. Matrix A is a __ by __.
2 x x 2
Therefore the product WILL exist. It will be a ___ by ___ matrix.

7. Product will be a ____ x ____ matrix.
Process to Multiply Matrices:
2 x x 2
Product will be a ____ x ____ matrix.
AB =

8. AB =

9. Ex. 2 Find the product given  
a) JK b) KJ

10. Ex. 3 Find the product given
a) RW b) WR

11. Ex. 4 Find each product given
BA b) (CB)A

12. ASSIGNMENT:
Textbook p. 577 – 578
#3, 7, 17, 33 – 35, 39