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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:
