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HP Forum Archive 12

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Inconsistent Results #2 and #3: 12c vs. 12c Platinum
Message #1 Posted by Gene on 13 May 2003, 10:28 a.m.

#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?
Message #2 Posted by Vieira, Luiz C. (Brazil) on 13 May 2003, 11:55 a.m.,
in response to message #1 by Gene

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
Message #3 Posted by Gene on 13 May 2003, 12:04 p.m.,
in response to message #2 by Vieira, Luiz C. (Brazil)

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
Message #4 Posted by Patrick on 13 May 2003, 6:58 p.m.,
in response to message #1 by Gene

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.


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