HP HP-18C - Halting and Restarting the IRR% Calculation; Storing a Guess for IRR

• Case 3: The HP-18C displays a negative answer and no message.
This is
the only answer.
• Case 4: The HP-18C displays the message:
MANY OR NO SOLUTIONS;
INPUT
GUESS [STO]{IRR%)
The calculation is very complex. It may involve more than one pos-
itive
and/or negative answer or there may be no solution. To
continue the calculation, you must store a guess.
• Case 5: There is no answer. The HP-18C displays:
t~O SOLUT I Ot~
This situation may have been caused by a mistake made in keying
in
the cash flows. Review the number list for typing mistakes or
incorrect signs. One thing to look for is a mistake in entering the
sign of a cash flow. There can be no solution without at least one
positive and one negative cash flow.
Halting and Restarting the IRR% Calculation
The search for IRR% may take a relatively long time. You can halt the
calculation at any time by pressing any key. The HP-18C then dis-
plays the current estimate for IRR%. You can resume the calculation
by:
• Pressing
I 5TO l ImB while the current estimate is displayed in the
calculator line . This continues the calculation from where it left off.
• Storing a guess for IRR%,
discussed below.
Storing a Guess for IRR%
You can enter a guess for IRR% at these times:
• Before
beginning the IRR% calculation. If you have some idea what
the answer should be, this may reduce the time required to calcu-
late
an answer.
• After
you've halted the IRR% calculation.
• After
the HP -18C has halted the calculation due to any of the cases
listed above . For cases 3 and 5, however, no (other) solutions will
be found.
170 B: More About HP-18C Calculations