HP HP-11C

Section 10
Applications Programs
Matrix Algebra
This program calculates the determinant and inverse of a 3 X 3
matrix (if it exists, i.e. det. # 0) and, with a minor program
manipulation, the solution to the system of linear equations
represented by the matrix.
Equations:
a;; a2 aj b, X1
A= asz; Gz asj B = by X= X2
asz; azz asg b3 X3
- hn
Qoo Q23 a2 a3 a2 a3
azs ass azz as3 Az asz3
1 az; agg ap; ag an a3
det A as asy az; ass az; a3
asz; az a;; ap2 a; ap
asz; az asz; asz ag Az
where Cis theinverse of A,
det A = a; (agag; —aggagy) —ajy(ag ags — agzas;)
+aj3(ag azy —agas;)
b
=ad — be.
d
c
140