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From: soper@maxzilla.encore.com (Pete Soper)
Newsgroups: comp.lang.pascal
Subject: Re: Needed:Trig Func arccos
Message-ID: <13309@encore.Encore.COM>
Date: 20 Nov 90 01:33:26 GMT
References: <1990Nov19.235515.24772@massey.ac.nz>
Sender: news@Encore.COM
Lines: 16

From article <1990Nov19.235515.24772@massey.ac.nz>, by T.Moore@massey.ac.nz (T. Moore):
>>   Arccos(x) = PI/2 - Arctan(x /sqrt(1 - x*x))
>>   Arcsin(x) = Arctan(x/sqrt(1-x*x))
>>   All angles returned are, of course, principle angles.
>>   Bob Beauchaine
> 
> This is fine, so long as your picture is not too complicated. Otherwise

  But think of how many pictures he can process in the time it would take to
implement an optimal arccos function. So while he is using this derived 
function he has got the freedom of time to make it fast, either with tables
or a full implementation using something like Cody and Waite.
  Sorry for the deletions but my mailer is ruthless about posted vs followups.
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Pete Soper (soper@encore.com)                           +1 919 481 3730
Encore Computer Corp, 901 Kildaire Farm Rd, bldg D, Cary, NC 27511  USA