Section 10: Applications Programs; Matrixalgebra - HP -11C Owner's Handbook Manual

Section 10
Matrix Algebra
Equations:
My) MQ O43 by xy
A=
| ag, agg
agg B=
| by X= | x
43) 432 Gag by Xg
422 Gash [412 213 G12 435
292 Gas 232 233 G22 2g
eee | 221 23 yy M3 M1 yg
det A 43, A353 @3 agg Gy) 23
2, G22) [411 G2 411 G12
43) O32 431 932 42 420
where C is the inverse of A,
det A = aj; (ag2@93 ~ ag3@g9) ~ 019( @91 439 ~ 42341)
+ a3(491 432 — 422431)
and
@ Ol d—b
eal" C.
140
Ot
Re ee Re
Section 10: Applications Programs 144
AX = Bis solved by X = CB, viz.,
422 G23 212 213 432 243
by —bg +b3
G32 M33 232 233 422 apg
my
x, 1 2g) Gzx Qi, F413 bef a
2 y= —b; + bg —b3
x3 det A a3) O33 23, Aas Jaz, G23
Gg Gap G11 F412 be Sad F
by — bg +b
a3) 432 231 2g2 421 G22
Note:
¢ Matrix operations can be especially prone to roundoff error. In
certain cases this error may significantly affect the program
results.
e If you have several sets of simultaneous equations to solve,
key in the determinant routine to find the determinants for
each 3X3 matrix. Replace the determinant routine with the
simultaneous equations routine and store the respective
determinant in Rp for each calculation.
4, a2 0
* A2X2 matrix should be stored as | ag, ago 0
0 0 1
® Error 0 will be displayed if the matrix entered is singular.