HP HP-15C - Page 155

Section 12: Calculating with Matrices 155
For ÷, the matrix specified in the X-register is replaced by its LU
decomposition. The ÷ function calculates X
1
Y using a more direct
method than does ∕ and *, giving the result faster and with improved
accuracy.
Example: Using matrices A and B from the previous example, calculate
C = A
T
B.













1797
531
954
321
and BA
Keystrokes
Display
l>
A
A
2
3
Recalls descriptor for matrix A.
l>
B
b
2
3
Recalls descriptor for matrix B
into X-register, moving matrix
A descriptor into Y-register.
´<
C
b
2
3
Designates matrix C as result
matrix.
´> 5
C
3
3
Calculates A
T
B and stores
result in matrix C, which is
redimensioned to 3×3.
The result, matrix C, is











1689066
955137
733929
C
.