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From: "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu>
Newsgroups: comp.lang.fortran
Subject: Re: Angle Units For Trig Functions
Date: Thu, 24 Oct 2024 05:31:13 -0000 (UTC)
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On Thu, 24 Oct 2024 05:22:53 +0000, Lawrence D'Oliveiro wrote:

> On Thu, 24 Oct 2024 05:06:37 -0000 (UTC), Steven G. Kargl wrote:
> 
>> For sin(x), argument reduction will give sin(0) = 0, exactly. That's one
>> angle.
> 
> More generally, it gives sin(x) ≃ x, for uncountably many angles.
> 
>> For sind(x), argument reduction will give sind(x) = 0, exactly,
>> for countable many angles.
> 
> But it never gives sind(x) anywhere close to x.

Never claimed sind(x) for x near 0 was exact.

It is, however, for floatin point arithmetic,
correct to less than or equal to 0.5 ULP.  Now,
got read Goldberg.

-- 
steve