HP 38g Graphing Calculator - Manual (Page 137)

Multiplying
Two Matrices
Multiplication of two matrices is not commutative. The
number of columns of the first matrix must equal the number
of rows of the second matrix.
Assume that Ml still contains [[1,2],[3,4]] and M2 still
contains [[5,6],[7,8]].
|A...z[M 1 0 [A...z|M 2
ENTER
Rns/2
m*M2
[ C 3 , 4 ] , C 5 , 6 ] ]
[ t l 9 , g g 3 , C 4 3 , 5 0 ] ]
Bévili
Dividing by a
Square Matrix
The result has the same number of rows as the first matrix and
the same number of columns as the second matrix.
To multiply a matrix by a vector, enter the matrix first, then
the vector. The number of elements in the vector must equal
the number of columns in the matrix.
For division of a matrix or a vector by a square matrix, the
number of rows of the dividend (or the number of elements,
if it is a vector) must equal the number of rows in the divisor.
Assume that Ml still contains [[1,2],[3,4]] and M2 still
contains [[5,6],[7,8]].
|A...z|M 1 0 |A...z|M 2
ENTER
The result is M2 * M 1 .
mm
M1*M2
Cn9,22],C43,5033
M1/M2
__________[ [ 5 , 4 ] , [ - 4 , - 3 3 3
Inverting a You can invert a square matrix in Home by typing the matrix
Matrix (or its variable name) and pressing ■ [x“'] | enter ]. (Or you
can enter INVERSE (matrixname) in Home.)
Negating Each You can change the sign of each element in a matrix by
Element pressing | - x | before the matrix name.
Using Matrices 6-7