Accuracy of HP Financial Calculators - Canadian mortgage

[Jeff_Kearns]

(04-07-2014 07:49 PM)Dieter Wrote:  Both the 42s and the 50G feature ln1+x and e^x-1, so they are able to obtain the correct 12-digit interest rate as 0,248451672465%. This again leads to the correct result, which in the above list is exclusively returned by the 30B.

So if the 12-digit machines don't get it right it's not their fault. It's sloppy programming in case of the 42s and 50G. Calculators that do not offer ln1+x need a workaround to get similar accuracy.

Thank you for this excellent reply! Although it has been 3 months since my original post, I have learned something valuable about calculator precision and the use of ln1+x, e^x-1, and hyperbolic workarounds to get the most out my calculators.

The HP-15C result is now the same as that of the 12C (to ten digits), the 42s correct to 12 digits, and the 32sII correct to 11 digits. My programming will be just a little less sloppy from here on in!

Jeff Kearns