154  Section 12: Calculating with Matrices 
 
Calculates B - A and stores 
values in redimensioned result 
matrix C. 
 
Matrix Multiplication 
With matrix description in both the X- and Y-registers, you can calculate 
three different  matrix products. The table below shows  the  results of the 
three functions for a matrix X specified in the X-register and a matrix Y 
specified  in  the  Y-register.  The  matrix  X
-1
  is  the  inverse  of  X,  and  the 
matrix Y
T
 is the transpose of Y. 
 
* Result is stored in result matrix. For ÷, the 
result matrix can be Y but not X. For the others, 
the result matrix must be other than X or Y. 
Note: When you use the ÷ function to evaluate the expression 
A
-1
B, you must enter the matrix descriptors in the order B, A rather 
than in the order that they appear in the expression.
*
 
The  value  stored  in  each  element  of  the  result  matrix  is  determined 
according to the usual rules of matrix multiplication. 
For > 5, the matrix specified in the Y-register isn't changed by this 
operation, even though its transpose is used. The result is identical to that 
obtained using > 4 (transpose) and *. 
  
*
 This is the same order you would use if you were entering b and a for evaluating a
-1
b = b/a