(42S) TVM Program for HP 42S
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05-23-2014, 11:02 AM
(This post was last modified: 06-15-2017 01:29 PM by Gene.)
Post: #1
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(42S) TVM Program for HP 42S
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05-25-2014, 03:10 PM
(This post was last modified: 05-27-2014 10:24 AM by Jeff_Kearns.)
Post: #2
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RE: TVM Program for HP 42S
(05-23-2014 11:02 AM)Ender Wrote: A TVM program for HP 42S. There is a much shorter (albeit less extravagant) 31 step version here for those who don't wish to enter 253 lines of code: An accurate TVM equation written as a program for the HP42S Solver. n number of periods i interest rate PMT periodic payment PV present value FV future value B/E BEGIN/END Solve equation: PMT*(i1-1)*(1/i+p)+PV*i1+FV=0 where (i1-1) = e1^(n*ln1(i)) and i1 = e^(n*ln1(i)) and ln1(x) = ln(1+x) and e1(x) = e^x-1 p=0 for END, p=1 for BEGIN The use of ln1+x and e^x-1 prevents the loss of significant digits for small values of i. Consider these extreme examples for accuracy checking: Example 1: n=63 i=0.00000161 PV=0 PMT=-1,000,000 END Mode (set B/E=0 in Solver) Solving for FV: HP 42S: 63,000,031.4434 (correct is 63,000,031.4433) Example 2: n=31536000 i=10/n PV=0 PMT=-0.01 END Mode Solving for FV: HP 42S: 331,667.006689 (correct is 331,667.006691) You might compare these results using the "normal" TVM equation, found in many manuals ![]() E.g. using the TVM equation in the 42S manual, we get 62,921,744.4422 and 311,565.594018 respectively. The program: 00 {91-Byte Prgm } 01 LBL "TVM" 02 MVAR "N" 03 MVAR "I%" 04 MVAR "PV" 05 MVAR "PMT" 06 MVAR "FV" 07 MVAR "B/E" 08 RCL "I%" 09 100 10 / 11 LN1+X 12 RCL* "N" 13 E^X-1 14 RCL* "PMT" 15 RCL "I%" 16 100 17 / 18 1/X 19 RCL+ "B/E" 20 * 21 RCL "PV" 22 RCL "I%" 23 100 24 / 25 LN1+X 26 RCL* "N" 27 E^X 28 * 29 + 30 RCL+ "FV" 31 END |
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05-25-2014, 07:34 PM
Post: #3
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RE: TVM Program for HP 42S
This is my version.
Shorter, and also works for I%=0: Code: 00 { 78-Byte Prgm } Cheers, Werner 41CV†,42S,48GX,49G,DM42,DM41X,17BII,15CE,DM15L,12C,16CE |
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