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Inconsistent Results #2 and #3: 12c vs. 12c Platinum - Printable Version

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Inconsistent Results #2 and #3: 12c vs. 12c Platinum - Gene - 05-13-2003

#2: Find the PV of 63 payments of $1,000,000 at the interest rate of 0.00000161% (small, but it isn't ZERO).

12c: -62,999,967.54

12c Platinum: -62,999,967.52

#3: Find the remaining balance after making 360 payments of $1,125.75 on a loan of $100,000 at an interest rate of 13.25%, compounded monthly.

Enter:

360 N
13.25 g 12/ (use the 12 divide blue shifted-function of the i key)
100000 CHS PV
1125.75 PMT
FV

12c: 108.8761800

12c Platinum: 108.8761785

My guess here is that the Platinum is more accurate.

Still, the 2 versions should not give different results!

Gene


Have you tried the HP19BII? - Vieira, Luiz C. (Brazil) - 05-13-2003

Hi, Gene;

I tried the three problems in both HP19BII and the TVM SOLVER in the HP48G.

#1 - both gave -1,237,786.93443

#2 - both gave -62,999,967.5424

#3 - both gave 108.87472648

About #1: shouldn't the sequence

 1.15 [ENTER] 26 [1/x] [y^x] 1 [-] 100 [×] [i]
be rounding actual interest rate value? Final magnitude gives a .54 %change from expected result and given result. It's somewhat big, if we consider the amount of money...

My US$ 0.02 contribution.

Luiz C. Vieira - Brazil


and 18c results - Gene - 05-13-2003

Correct about the process to enter the interest rate, but that's how the results were produced in the PPC Journal article on improving the PPC ROM FI program (FIN program). I didn't want to change it.

18c gives the same answer to #1 and #2 as the 19BII

However, it gives a different answer to #3

18c: 108.874741020


Re: Inconsistent Results #2 and #3: 12c vs. 12c Platinum - Patrick - 05-13-2003

If the Platinum is more accurate then I disagree with you: the two versions should give different results.

HP should not be bound to reproduce erroneous results only to please the gods of consistency. They have to be allowed to make corrections when errors have been discovered.