HP -15C Advanced Functions Handbook page 31

Section 1: Using j SOLVE | Effectively 29
The basic equation used for the financial calculations is
PMT A
PV + [1 - (1 + I'/lOO)'
71
] + FV(1 + i/lOOr
1
= 0
z/100
where i ^ 0 and
for end-of-period payments
\ * ^ +1/100 for beginning-of-period payments.
The program has the following characteristics:
|SOLVE| is used to find i. Because this is an iterative function,
solving for i takes longer than finding other variables. It is
possible to define problems which cannot be solved by this
technique. If (SOLVE | can't find a root, Error 4 is displayed.
• When finding any of the variables listed on the left below,
certain conditions result in an Error 4 display:
= -PVi/(lOOA)
(PMTA-FVi/lOO)/(PMTA+PVi/WO)^0
i^-100
i | SOLVE | can't find a root
PV iX-100
PMT n = 0
i = 0
fs£-100
FV isg-100
If a problem has a specified interest rate of 0, the program
generates an Error 0 display (or Error 4 when solving for
PMT).
• Problems with extremely large (greater than 10
6
) or extremely
small (less than 10~
6
) values for n and i may give invalid
results.
• Interest problems with balloon payments of opposite signs to
the periodic payments may have more than one mathemati-
cally correct answer (or no answer at all). This program may
find one of the answers but has no way of finding or
indicating other possibilities.
Keystrokes Display
C1T|[P/R I Program mode.
( T I C L E A R l P R G M l 000-