[Maxima] strange behaviour with simple decimals
belanger at truman.edu
Wed Apr 11 11:13:00 CDT 2007
"Stavros Macrakis" <macrakis at alum.mit.edu> writes:
> It may be worth noting that both Axiom and my pocket calculator give
> the correct answer to 3*1.4^2.
> To how many digits? What are the results for (3*1.4^2)-5.88 or (5/9)*9-5? or sin
(1) -> (3*1.4^2) - 5.88
(2) -> (5/9)*9-5
Type: Fraction Integer
(3) -> sin(3.1415926535897932385/4)-sqrt(1/2)
(3) 0.1 E -19
> I don't know how Axiom operates. This may just be a rounding-on-display issue, or it
> may actually calculate the answer differently internally (decimal floats? rationals?)
I don't know much about the Axiom internals, either.
> Your pocket calculator may operate in decimal floating-point, in which case it will
> get exact answers for 3*1.4^2 and the like, but not for other calculations.
Interesting. I realize that calculators typically only give
approximations, but when does it give the wrong answer when you'd
expect the right one? (I have no doubt such cases exist; I just don't
know one offhand.)
> Do you have any suggestions on how to improve things?
No; I'm not being very helpful.
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