HP 50g Graphing Calculator - Manual (Page 351)

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: