# Addition And Subtraction; Multiplication - HP 48gII User Manual

Graphing calculator.

Consider a pair of matrices A = [a
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
± b
elements c
= a
. Some examples in ALG mode are shown below using
ij
ij
ij
the matrices stored above (e.g., @A22@ + @B22@)
In RPN mode, the steps to follow are:
A22 ` B22`+
A23 ` B23`+
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
kA = [c
]
= [ka
]
. In particular, the negative of a matrix is defined by
×
×
ij
m
n
ij
m
n
the operation -A =(-1)A = [-a
matrix by a scalar are shown below.
and B = [b
]
]
×
ij
m
n
ij
m
A22 ` B22`-
A23 ` B23`-
A32 ` B32`-
by a scalar k results in the matrix C =
]
×
ij
m
n
]
. Some examples of multiplication of a
×
ij
m
n
×
n
]
has
×
ij
m
n
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