HP 49g+ - Manual (Page 123)

Page 9-6
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
The inverse of a square matrix A is the matrix A
-1 such that A ⋅ A -1 = A -1 ⋅ 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: