From: Christopher MCKEOWN's News
Subject: cos-1
Date: 
Message-ID: <959045703.710105@totara.its.vuw.ac.nz>
how do i achieve the inverse of cosine using lisp
From: Coby Beck
Subject: Re: cos-1
Date: 
Message-ID: <ITmW4.21970$t8.277054@news.bc.tac.net>
would that be (acosh arg) ?

http://gemini.iti.informatik.tu-darmstadt.de/cl-hyperspec/Body/fun_sinhcm_co
_coshcm_atanh.html#cosh

Coby

Christopher MCKEOWN's News <··········@scs.vuw.ac.nz> wrote in message
·····················@totara.its.vuw.ac.nz...
> how do i achieve the inverse of cosine using lisp
>
>
From: Hartmann Schaffer
Subject: Re: cos-1
Date: 
Message-ID: <392ac25a@news.sentex.net>
Since when is acosh the inverse of cosine?  i always thought it was acos

In article <·····················@news.bc.tac.net>,
	"Coby Beck" <·····@mercury.bc.ca> writes:
> would that be (acosh arg) ?
> 
> http://gemini.iti.informatik.tu-darmstadt.de/cl-hyperspec/Body/fun_sinhcm_co
> _coshcm_atanh.html#cosh
> 
> Coby
> 
> Christopher MCKEOWN's News <··········@scs.vuw.ac.nz> wrote in message
> ·····················@totara.its.vuw.ac.nz...
>> how do i achieve the inverse of cosine using lisp
>>
>>
> 
> 

-- 

Hartmann Schaffer
From: Coby Beck
Subject: Re: cos-1
Date: 
Message-ID: <959180231086@NewsSIEVE.cs.bonn.edu>
my trig memories are very foggy and long unused....(hence the question rather than
statement!).  The useful part of my post was meant to be the link where many of the
lisp trig functions are documented (and the implied advice to RTFM!)....though i now
see acos is there on another page too.

Coby

Hartmann Schaffer <··@inferno.nirvananet> wrote in message
·············@news.sentex.net...
| Since when is acosh the inverse of cosine?  i always thought it was acos
|
| In article <·····················@news.bc.tac.net>,
| "Coby Beck" <·····@mercury.bc.ca> writes:
| > would that be (acosh arg) ?
| >
| >
http://gemini.iti.informatik.tu-darmstadt.de/cl-hyperspec/Body/fun_sinhcm_coshcm_atanh.
html#cosh
| >
| > Coby
| >
| > Christopher MCKEOWN's News <··········@scs.vuw.ac.nz> wrote in message
| > ·····················@totara.its.vuw.ac.nz...
| >> how do i achieve the inverse of cosine using lisp
| >>
| >>
| >
| >
|
| --
|
| Hartmann Schaffer
|
From: Anders Vinjar
Subject: Re: cos-1
Date: 
Message-ID: <copr9atd771.fsf@clara.uio.no>
try using acos

 (acos (cos 2.0)) => 2.0
From: J.L. Perez-de-la-Cruz
Subject: Re: cos-1
Date: 
Message-ID: <392C2897.3C77B929@lcc.uma.es>
Christopher MCKEOWN's News wrote:
> 
> how do i achieve the inverse of cosine using lisp

Short and unaccurate answer: function acos

Long and accurate answer:
There is no such thing as "the inverse of cosine",
neither in R nor in C. Slippery subject, that of
principal values and branch cuts... 


---------------------
Jose-Luis Perez-de-la-Cruz
ETSI Informatica
POB 4114
MALAGA 29080 SPAIN
Tlf +34 952 132801
Fax +34 952 131397
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comp.lang.lisp / 2000 / may