210 likes | 472 Views
4.5, 4.6 2 x 2 and 3 x 3 Matrices, Determinants, and Inverses. Date: _____________. Matrices are multiplicative inverses. Page 199 – 2 definitions Multiplicative Identity Matrix Must be a square matrix, 2 x 2, 3 x 3, 4 x 4, etc. Has 1’s in the main diagonal and 0’s elsewhere
E N D
4.5, 4.62 x 2 and 3 x 3 Matrices, Determinants, and Inverses Date: _____________
Matrices are multiplicative inverses • Page 199 – 2 definitions • Multiplicative Identity Matrix • Must be a square matrix, 2 x 2, 3 x 3, 4 x 4, etc. • Has 1’s in the main diagonal and 0’s elsewhere • Multiplicative Inverse of a Matrix • when multiplying a matrix by its inverse, we get the identity matrix
Matrices are multiplicative inverses Show that these two matrices are multiplicative inverses Use your calculator
Objective - To evaluate the determinates of 2 x 2 and 3 x 3 matrices. Find the Determinant Determinant can be labeled either way
Objective - To evaluate the determinates of 2 x 2 and 3 x 3 matrices. Find the Determinant Determinant
Evaluate the Determinant for each Matrix When the determinant = 0, then that matrix has NO INVERSE
Find the determinant of each 3x3 Matrix. Determinant Take the first 2 columns and rewrite them outside
Fun? Use your Calculator Matrix, over to MATH, then det(, then go to Matrix, we want matrix A
Determinant and its use The determinant is used to find our inverse We will use our calculator to find the inverse. Type in: Find the determinant first: Therefore, it has an inverse
Determinant and its use The determinant is used to find our inverse We will use our calculator to find the inverse. Type in:
Find the inverse of the matrix If A didn’t have an inverse, you’d get the message ERR: SINGULAR MAT
Checking your answers. If you multiply inverses, you will always get the identity matrix. This is a way you can check your answers
Linear Equations Matrix Equations Solve for X.