Interval Arithmetic - x-squared and other functions

[johnb]

(10-03-2022 07:12 AM)Gjermund Skailand Wrote:  Keep in mind there is a difference between squaring an interval number, and how it would be different from multiplying two interval numbers that just happends to be similar.
There are a few examples of interval arithmetic on the longfloat library at https://www.hpcalc.org/hp49/math/numeric/lf393.zip
br Gjermund

Yes, I had suspected as much. Intervals don't obey all of the rules that integers and reals do.

For fun, I've tried to work out most of the principles of interval arithmetic for myself. There aren't many areas of modern mathematics where the topics are current, but where anyone other than a professional mathematician could get anywhere doing that.

But now, I think I just want to finish my program library and have it be correct. I anticipate that looking at the HP-49 library you mentioned will help a lot. Some of it might even be easily ported to the HP-48 series.