HP HP-28S - Finding a Minimum or Maximum

The Solver menu shows all the variables in the current equation (only
X in this example).
Store
the digitized estimate in variable X.
Ijlr:=~; iiiGffiliiB:Jii: c:::Jijij!ft)JImc:::Jti§[icr)'ic:::Jiiiiic:::Jiiiill
Although the digitized point contained two coordinates, the Solver
will
use only the first coordinate as an estimate.
Now solve for X.
!P.--
{gn Reversal
1: -1. 36
ITJGffilc:::Jc:::Jc:::Jc:::J
The message::: i gn Rever s.:ll indicates that the Solver found an
approximate solution, correct to 12 digits. If the Solver found an exact
solution, it
would display the message Zet- o. These messages, called
qualifying messages, are discussed in HSOLVE
H
in the Reference
Manual.
Return to the normal stack display.
@illl =-:---3: ------,1
2:
1: -1. 36
[::::[:JGffilc:::Jc:::Jc:::Jc:::J
Finding a Minimum or Maximum
To find the zero of an expression, the Solver samples points on the
graph, starting with your estimate, and tries to find points closer to
the x-axis. If your estimate is quite close to a positive local minimum or
a negative local maximum, there are no points nearby that are closer to
the x-axis. In this case, the Solver finds that extremum (minimum or
maximum) rather than a zero. (Generally the Solver won't Hget stuck"
at an extremum unless your estimate forces it there.) ~
100 8: The Solver