(71B) calculate interest rate

12202019, 10:10 PM
Post: #3




RE: (71B) calculate interest rate
(12202019 08:36 PM)Joe Horn Wrote: Wouldn't using the HP71's builtin EXPM1 and LOGP1 functions be even more accurate? Thanks! I don't know HP71B had both expm1 and logp1 builtin. The revised code is much shorter. Code: 10 INPUT "n, fv, pv, pmt ? ";N,F,P,M >RUN n, fv, pv, pmt ? 168, 10925.76, 0, 45 4.79863130882E3 655.6829061 5.33181256535E3 1255.8749515 4.21615468581E3 41.4514876 4.17684617474E3 1.4838737 4.17538677149E3 .0035171 4.17538330417E3 .0000003 4.17538330387E3 0 4.17538330387E3 FYI, 1st column is interest rate, 2nd column is error in FV (thus function named FNF) Example, I=0.479863%, calculated FV=11581.44, underestimated true FV by $655.68 Playing emulator interactively, this is unexpected ... >FNROOT(I1, .5*I1, FNF(FVAR)) MATH ERR:Kybd FN in FNROOT/INTEGRAL 

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Messages In This Thread 
(71B) calculate interest rate  Albert Chan  12202019, 04:14 PM
RE: (71B) calculate interest rate  Joe Horn  12202019, 08:36 PM
RE: (71B) calculate interest rate  Albert Chan  12202019 10:10 PM
RE: (71B) calculate interest rate  JF Garnier  12212019, 03:44 PM
RE: (71B) calculate interest rate  Albert Chan  12222019, 03:07 PM
RE: (71B) calculate interest rate  Albert Chan  12292019, 02:46 PM
RE: (71B) calculate interest rate  Albert Chan  01022020, 05:43 PM
RE: (71B) calculate interest rate  Albert Chan  01062020, 09:16 PM
RE: (71B) calculate interest rate  Albert Chan  02132020, 03:41 PM

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