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+--- Thread: (29C) Accurate TVM for HP-19C/HP-29C (/thread-469.html)
(29C) Accurate TVM for HP-19C/HP-29C - Jeff_Kearns - 01-19-2014 07:04 PM
The HP-29C does not have the HP SOLVE functionality of later models starting with the HP-34C and implemented in the HP-15C, HP-41 Advantage module. This program combines the Equation Solver for the HP-19C/HP-29C published by Stefan Vorkoetter in the old software library with the accurate TVM code used in the HP-34C program, which does not have Recall Arithmetic, into a 71 line program effectively turning your HP-29C into a reliable financial calculator (insofar as standard TVM calculations are concerned).
Code:
LINE KEYSTROKES COMMENTS
01 g LBL 0 -main entry point
02 STO 0 -store index of variable to solve for
03 roll dn
04 STO .2 -store second guess
05 roll dn
06 STO .1 -store first guess
07 STO i -compute f1 = f(R1,..,Ri1,..,Rn)
08 GSB 9
09 STO .0
10 RCL .2 -compute f2 = f(R1,..,Ri2,..,Rn)
11 STO i
12 g LBL 1
13 GSB 9 -the equation to be solved must begin at LBL 9
14 STO .2
15 RCL .1 -compute Ri2 <- (Ri1 f2 - Ri2 f1) / (f2 - f1)
16 x
17 RCL i
18 STO .1 -move old Ri2 to Ri1 while we're here
19 RCL .0
20 x
21 -
22 RCL .0
23 RCL .2
24 STO .0 -move old f2 to f1 while we're here
25 x<>y
26 -
27 /
28 STO i -save new value for Ri2
29 RCL .1 -compare to previous guess
30 X≠Y -keep going until they're the same
31 GTO 1
32 g RTN -end of SOLVER routine that can be used with any MISO equation
33 g LBL 9 -begin entering TVM equation at this step
34 RCL 2
35 EEX
36 2
37 ÷
38 ENTER
39 ENTER
40 1
41 +
42 LN
43 X<>Y
44 LSTx
45 1
46 X≠Y
47 -
48 ÷
49 *
50 RCL 1
51 *
52 e^x
53 RCL 3
54 X<>Y
55 *
56 LSTx
57 1
58 -
59 RCL 4
60 *
61 EEX
62 2
63 RCL 2
64 ÷
65 RCL 6
66 +
67 *
68 +
69 RCL 5
70 +
71 RTNUsage instructions:
1. Store 4 of the following 5 variables as follows, using appropriate cash flow conventions:
N STO 1 --- Number of compounding periods
I STO 2 --- Interest rate (periodic) expressed as a %
B STO 3 --- Initial Balance or Present Value
P STO 4 --- Periodic Payment
F STO 5 --- Future Value
and store the appropriate value (1 for Annuity Due or 0 for Regular Annuity) as
B/E STO 6 --- Begin/End Mode. The default is 0 for regular annuity or End Mode.
2. Leave the floating variable un-stored, but enter two guesses (if desired), each followed by the ENTER key; and
3. Enter the floating variable register number followed by GSB 0
Example from the HP-15C Advanced Functions Handbook-
"Many Pennies:
A corporation retains Susan as a scientific and engineering consultant at a fee of one penny per second for her thoughts, paid every second of every day for a year.
Rather than distract her with the sounds of pennies dropping, the corporation proposes to deposit them for her into a bank account in which interest accrues at the rate of 11.25 percent per annum compounded every second. At year's end these pennies will accumulate to a sum
total = (payment) X ((1+i/n)^n-1)/(i/n)
where payment = $0.01 = one penny per second,
i = 0.1125 = 11.25 percent per annum interest rate,
n = 60 X 60 X 24 X 365 = number of seconds in a year.
Using her HP-15C, Susan reckons that the total will be $376,877.67. But at year's end the bank account is found to hold $333,783.35 . Is Susan entitled to the $43,094.32 difference?"
31,536,000 STO 1
(11.25/31,536,000) STO 2
0 STO 3
-0.01 STO 4
5 GSB 0
The HP-29C gives the correct result: $333,783.35.