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From: SLSW2@cc.usu.edu (Roger Ivie)
Newsgroups: comp.sys.handhelds
Subject: Re: Two questions...
Message-ID: <36159@cc.usu.edu>
Date: 25 Sep 90 16:57:03 GMT
References: <1990Sep24.183934.575@rick.cs.ubc.ca>
Followup-To: comp.sys.handhelds
Lines: 25

In article <1990Sep24.183934.575@rick.cs.ubc.ca>, b3300876@rick.cs.ubc.ca (george kai yee chow) writes:
> 
> The second is wrt the cosine function. I was doing some 
> geometry problem and needed to evaluate cos(pi/3) (I know, I 
> know, I should know it but I thought I might as well fire up
> my 48 just for fun). My 48sx returned 0.4999..., not 0.5. 
> sin(pi/6) does return 0.5 though. Why is this? 
> 
One of the more interesting things I encountered when I bought my first
HP calculator (a 31E) was a long discussion in the manual about this sort
of problem (I've still got the manual, but it's not handy. If anyone's
interested, I can find a direct quote).

The gist of the discussion was that since the calculator could not really
use pi but only a 10-digit approximation of pi, the result of the calculator
is accurate. It is returning the cosine of precisely that 10-digit
approximation of (pi/3).
-- 
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Roger Ivie

35 S 300 W
Logan, Ut.  84321
(801) 752-8633
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