HP 49g 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

The inverse of a square matrix A is the matrix A-1such 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:

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