The Identity Matrix; The Inverse Matrix - HP 50g User Manual

The identity matrix

The identity matrix has the property that A I = I A = A . To verify this
property we present the following examples using the matrices stored
earlier on. Use function IDN (find it in the MTH/MATRIX/MAKE menu) to
generate the identity matrix as shown here:

The inverse matrix

-1 -1 -1
The inverse of a square matrix A is the matrix A such that A A = A A
= I , where I is the identity matrix of the same dimensions as A . The inverse
of a matrix is obtained in the calculator by using the inverse function, INV
(i.e., the Y key). Examples of the inverse of some of the matrices stored
earlier are presented next:
To verify the properties of the inverse matrix, we present the following
multiplications:
Page 9-7