L4-5/L4-6 Objective: Students will be able to evaluate determinants of matrices

A matrix is a table with rows and columns A square matrix is a matrix with the same number of columns as rows. A multiplicative identity matrix gives you a product with 1’s along the main diagonal and 0’s elsewhere. Multiplicative inverses are written as A and A- 1

 

Show that matrices A and B are multiplicative inverses. Additional Examples Show that matrices A and B are multiplicative inverses. 3 –1 7 1 0.1 0.1 –0.7 0.3 A = B =

Practice (on whiteboards) Are these multiplicative inverses?

Practice (on whiteboards) Are these multiplicative inverses?

Evaluate each determinant. 2 X 2 Matrices, Determinants, and Inverses LESSON 4-5 Additional Examples Evaluate each determinant. 7 8 –5 –9 a. det b. det c. det 4 –3 5 6 a –b b a

Practice Find the determinant

Ex 3: Evaluate the determinant of X = . 3 X 3 Matrices, Determinants, and Inverses 8 –4 3 –2 9 5 1 6 0 Ex 3: Evaluate the determinant of X = .

Ex 4:

Practice Find the determinant

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4. Homework 4.5 P207 #8-12e 4.6 P213 #1-4all 16 18