Online calculator simulators?

[toml_12953]

(07-10-2022 03:28 AM)pauln Wrote:  

(07-09-2022 09:17 PM)Albert Chan Wrote:  This has less to do with calculators, and more to do with math.

sin(9°) = sin(pi/20) ≈ pi/20
cos(sin(9°)°) ≈ cos(pi/20 * pi/180) ≈ 1 - (pi^2/3600)^2 / 2! ≈ 0.999996

We had lost 5+ digits precision, due to catastrophic cancellation.
That's why all calculator forensic test will lose 5 to 6 digits precisions.
This is true even if all calculations produce correctly rounded results!
[...]

This is a great observation. I have always found this test a little bit arbitrary and dubious, for the exact same reasons.

(It is a good test though to differentiate emulators from simulators.)

1 sin cos tan arctan arccos arcsin

in radians would have been a much better test.

The purpose of the original test was not to see how close a calculator could come to 9 but it

Quote:...seeks to answer the questions of who originally designed a particular calculator's chip set, what features of a particular calculator have been borrowed from earlier designs, and how has calculator technology spread among the manufacturers.

To use it for other purposes isn't the intent of the author.

Calculator Forensics