Halting And Restarting A Numerical Search; Entering Guesses - HP -18C Owner's Manual

• Case 3:
The HP-18C displays
TR'l AGAIt-l, BAD GUES : : :;E:::;:
and the guesses the solver used when the calculation was started
(or restarted). This indicates that the solver cannot begin the search
with the current guesses. Refer to
Entering Guesses,
below).
• Case 4:
The HP-18C displays
SOLUT
I
Ot~
NOT FOUND
because
the solver was unable to find a solution. Check to see if your for-
mula and stored values are correct.
If the formula is correct, you
may be able to find a solution by entering very good guesses.
Halting and Restarting the Numerical Search
When the solver is searching for a numerical solution (in other words,
when the solver is displaying sets of estimates), you can halt the cal-
culation by pressing any key. The HP-18C displays the best estimate
the solver has found so far, and the message I
~nERRUPTED .
You
can restart the search from where it left off by pressing the menu key
for the variable you are solving for. Or, you can restart the search
using your own guesses (refer to
Entering Guesses,
below).
Entering Guesses
Entering your own guesses serves two purposes. First, it can save time
by telling the solver where to start searching. Secondly, if more than
one solution exists, entering guesses can help the solver select the an-
swer you want. The closer your guesses are to the answer you want,
the better chance the solver has of finding it.
You can enter guesses at these times:
• Before beginning the calculation, after you've stored a value for ev-
ery variable except the unknown variable.
If you enter one guess,
the solver generates a second guess.
• After you've halted the numerical search.
• After the solver has returned an answer, and you wish to begin
searching for another answer somewhere else.
138 9: The Formula Solver