Presentation on theme: "4.7 Identity and Inverse Matrices. What is an identity? In math the identity is the number you multiply by to have equivalent numbers. For multiplication."— Presentation transcript:
What is an identity? In math the identity is the number you multiply by to have equivalent numbers. For multiplication it is one. 5 * 1 = 5, of course. How is this useful? If you need to have a denominator of 40 in the fraction
What is an inverse? The inverse is a number when multiplied by another number equals one.
The identity matrix is a square matrix with one down the diagonals In a 2 X 2In a 3 X 3
Find the matrices that when multiply together are the identity matrix. How do we find the inverse?
Find the inverse Find the determinant of 6 – ( - 8) = 14 We will flip the diagonal of top left and bottom right, then change the signs the bottom left to top right diagonal.
Putting the part together Take the determinant and put it under one and multiply it by the moved matrix.