HP 49g+, Руководство пользователя, Страница: 324 / 862

Page 11-2
Addition and subtraction
Consider a pair of matrices
A
= [a
ij
]
m
×
n
and
B
= [b
ij
]
m
×
n
. Addition and
subtraction of these two matrices is only possible if they have the same
number of rows and columns. The resulting matrix,
C
=
A ± B
= [c
ij
]
m
×
n
has
elements c
ij
= a
ij
±
b
ij
. Some examples in ALG mode are shown below using
the matrices stored above (e.g.,
@A22@ + @B22@
)
In RPN mode, the steps to follow are:
A22 ` B22 `+ A22 ` B22 `-
A23 ` B23 `+ A23 ` B23 `-
A32 ` B32 `+ A32 ` B32 `-
Translating the ALG examples to RPN is straightforward, as illustrated here.
The remaining examples of matrix operations will be performed in ALG mode
only.
Multiplication
There are different multiplication operations that involve matrices. These are
described next.
Multiplication by a scalar
Multiplication of the matrix
A
= [a
ij
]
m
×
n
by a scalar k results in the matrix
C
=
k
A
= [c
ij
]
m
×
n
= [ka
ij
]
m
×
n
. In particular, the negative of a matrix is defined by
the operation -
A
=(-1)
A
= [-a
ij
]
m
×
n
. Some examples of multiplication of a
matrix by a scalar are shown below.