[Patch, Fortran, Doc] Inverse hyperbolic functions

[Toon Moene]

Toon Moene wrote:
> Janus Weil wrote:
> 
>> Hi Dominique,
>>
>>> I agree that "Inverse hyperbolic *" is better than "Hyperbolic arc*"
>>> (when I was taught hyperbolic functions and their inverses some 45 years
>>> ago, they were denoted ch, sh, and th and the inverses argch, argsh,
>>> and argth, I have no idea about the today fashion!-).
>>>
>>> However the inverse hyperbolic functions appear in many places and
>>> not in non-Euclidian geometry only, so I am not very fond
>>> (to say the least) of "hyperbolic area". Why not
>>> "computes the inverse @var{X} of the hyperbolic * (@code{*(X)})."
>>> (or any suitable translation from Frenglish to native English!).
>>
>> well, I'm starting to think that there may be regional differences in
>> the naming of the inverse hyperbolics (though I'm not sure about
>> this)?
> 
> Perhaps.
> 
> A lot of people were brought up with Abramowitz and Stegun, which I have 
> downloaded (it's claimed to be a work of the US Government - and hence 
> in the public domain) and is accessible as (among other places !):
> 
> http://moene.org/~toon/abramowitz_and_stegun/
> 
> The (first) page that references ar(c)tanh is page 86:
> 
> http://moene.org/~toon/abramowitz_and_stegun/page_86.htm
> 
> Obviously, it calls it "Inverse hyperbolic <function>".

And, to be complete, the Fortran 2008 Standard will say:

ASINH(X) Inverse Hyperbolic Sine Function
                 (and mutatis mutandis for other functions).

So I think we should stick to that terminology in our documentation.

Kind regards,

-- 
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
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