Quote:
So finally, this is why the HP30S gets exactly 9.00000000000000000 when running the calculator forensics test. To see the real error, one should subtract the input argument of the test from the final result. That is, do:
arcsin(arcos(arctan(tan(cos(sin(9))))))-9
On the HP30S, the result is 0, leading one to believe that the HP30S is *really* accurate. But redo the test as:
arcsin(arcos(arctan(tan(cos(sin(9.1))))))-9.1
to foil its rounding near integers and see a result: 4.833288903E-11
Not all that great for a calculator that can do 24 digit calculations, eh?
I did the Rodger's 9.1 version of the forensics algorithm on my 10s and received 9.100000002602 . Does that suggest that the 10s isn't doing any of the funny arithmetic that Rodger was writing about?