HP 40gs, Руководство пользователя

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18-8 Matrices
To divide by a
square 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.
This operation is not a mathematical division: it is a left-
multiplication by the inverse of the divisor. M1/M2 is
equivalent to M2
–1
* M1.
To divide the two matrices M1 and M2 that you created
for the previous example, press the following keys:
M1
M2
To invert a matrix
You can invert a square matrix in HOME by typing the
matrix (or its variable name) and pressing x
–1
. Or you can use the matrix INVERSE command.
Enter
INVERSE
( matrixname ) in HOME and press
.
To negate each
element
You can change the sign of each element in a matrix by
pressing
before the matrix name.
Solving systems of linear equations
Example Solve the following linear system:
1. Open the Matrix
catalog and create a
vector.
MATRIX
2. Create the vector of the
constants in the linear
system.
5 7
1
2 x 3 y 4 z + + 5
x y z – + 7
4 x y – 2 z + 1
=
=
=
hp40g+.book Page 8 Friday, December 9, 2005 1:03 AM