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From: Neil <nddtwentyone@gmail.com>
Newsgroups: comp.lang.fortran
Subject: Re: Angle Units For Trig Functions
Date: Wed, 23 Oct 2024 21:21:41 -0000 (UTC)
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Steven G. Kargl <sgk@removetroutmask.apl.washington.edu> wrote:
> On Wed, 23 Oct 2024 06:25:02 +0000, Lawrence D'Oliveiro wrote:
> 
>> On Wed, 23 Oct 2024 07:59:24 +0200, R Daneel Olivaw wrote:
>> 
>>> Lawrence D'Oliveiro wrote:
>>>
>>>> On Wed, 23 Oct 2024 04:06:26 -0000 (UTC), David Jones wrote:
>>>> 
>>>>> Did you take a high school trigonometry class?
>>>> 
>>>> You seem obsessed with that.
>> 
>> So your favourite functions return an exact result for sin 30°. Do they 
>> return an exact result for cos 30° as well?
>> 
> 
> Nope.  For REAL x, COSD(x) returns an exact result for all N >= 0
> that satisfies 60+N*360 < 2**23.
> 

Could you give an example of where sind and cosd might be of use in a
piece of numerical software?