Section 12: Calculating with Matrices 165
Inverting a Complex Matrix
You can calculate the inverse of a complex matrix by using the fact that
(Z)
−1
= (Z
−1
).
To calculate the inverse, Z
−1
, of a complex matrix Z:
1. Store the elements of Z in memory, in the form either of Z
P
or of Z
C
.
2. Recall the descriptor of the matrix representing Z into the display.
3. If the elements of Z were entered in the form Z
C
, press ´ p to
transform Z
C
into Z
P
.
4. Press ´ > 2 to transform Z
P
into Z.
5. Designate a matrix as the result matrix. It may be the same as the
matrix in which Z is stored.
6. Press ⁄. This calculates (Z)
−1
, which is equal to (Z
−1
). The values
of these matrix elements are stored in the result matrix, and the
descriptor of the result matrix is placed in the X-register.
7. Press ´ > 3 to transform (Z
−1
) into (Z
−1
)
P
.
8. If you want the inverse in the form (Z
−1
)
C
, press | c.
You can derive the complex elements of Z
−1
by recalling the elements of
Z
P
or Z
C
and then combining them as described earlier.
Example: Calculate the inverse of the complex matrix Z from the previous
example,
A = Z
P
=
4 7
1 3
3
−
2
5 8
.
Keystrokes Display
l > A
A 4 2
Recalls descriptor of matrix A.
´ > 2
A 4 4
Transforms Z
P
into Z and
redimensions matrix A.
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