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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.lang.fortran
Subject: Re: Angle Units For Trig Functions
Date: Tue, 22 Oct 2024 20:50:27 -0000 (UTC)
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On Tue, 22 Oct 2024 07:14:22 -0000 (UTC), Steven G. Kargl wrote:

> On Tue, 22 Oct 2024 04:26:59 +0000, Lawrence D'Oliveiro wrote:
> 
>> On Sun, 20 Oct 2024 05:35:25 -0000 (UTC), Steven G. Kargl wrote:
>> 
>>> % gfcx -o z a.f90 && ./z 0.500000000      0.500089288
>>> 
>>> One of these values is exact, and one of these raises FE_INEXACT.
>> 
>> Does it work for 29° and 31° as well? What’s so special about 30°?
> 
> Really?  This is high school trig.
> 
> For units of degree, mathematically sin(30) = 1/2, exactly!.
> sin(30+n*360) = 1/2 is also exact.

What’s so special about 30°? Does that extend to 29° and 31° as well?