HP 50G, User Manual

Page: 351 / 887

Page 11-24
Press
`
to return to the numerical solver environment. To check that the
solution is correct, try the following:
•
Press
——
, to highlight the A: field.
•
Press
L @CALC@ `
, to copy matrix A onto the stack.
•
Press
@@@OK@@@
to return to the numerical solver environment.
•
Press
˜ ˜ @CALC@ `
, to copy solution vector X onto the stack.
•
Press
@@@OK@@@
to return to the numerical solver environment.
•
Press
`
to return to the stack.
In ALG mode, the stack will now look like this:
Let’s store the latest result in a variable X, and the matrix into variable A, as
follows:
Press
K~x`
to store the solution vector into variable X
Press
ƒ ƒ ƒ
to clear three levels of the stack
Press
K~a`
to store the matrix into variable A
Now, let’s verify the solution by using:
@@@A@@@ * @@@X@@@ `
, which results in the
vector [8.6917… -3.4109… -1.1301…], which is not equal to [15 5 22], the
original vector
b . The “solution” is simply the point that is closest to the three
lines represented by the three equations in the system, and not an exact
solution.
Least-square solution (function LSQ)
The LSQ function returns the minimum-norm least-square solution of a linear
system Ax = b, according to the following criteria: