MATINV

Syntax: MATINV matrix2,matrix1
Location: Math Package

The command MATINV takes the array matrix1, inverts it and stores the result in matrix2. 

If an array is multiplied by its inverted self, this gives the identity matrix.

Two conditions are absolutely necessary for MATINV to work:  
(a) DET (matrix1) <> 0   
(b) matrix1 and matrix2 must be square matrices

CROSS-REFERENCE:
It is highly recommended to check if DET is very close to zero after MATINV has been executed, if this is the case,  MATINV may have found a result which does not exist:   

IF ABS(DET) < 1E-6 THEN PRINT "dubious result"   

This works because MATINV calls DET internally.
