Matrix Multiplication - HP -15C Owner's Handbook Manual

154 Section 12: Calculating with Matrices
Keystrokes
-
The result is
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
T
matrix Y is the transpose of Y.
*
´ > 5
÷
* Result is stored in result matrix. For
Note: When you use the ÷ function to evaluate the expression
-1
A 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
Display
C 2
 
0 1 2

 
 
3 4 8
Pressing
result matrix can be Y but not X. For the others,
the result matrix must be other than X or Y.
3
Calculates B - A and stores
values in redimensioned result
matrix C.
-1
is the inverse of X, and the
Calculates*
YX
T
Y X
-1
X Y
÷
, the
*
-1
b = b/a