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Re: MathML 2.0 Last call

From: Leszek Sczaniecki <lsczan@concentric.net>
Date: Sat, 29 Apr 2000 09:38:00 -0400
Message-ID: <390AE5B7.CEBF6693@concentric.net>
To: www-math@w3.org
> Janet Daly wrote:
>
>  > This is the Last Call Working draft and the review period
>  > ends 30 April.
>

My short comment is about the names of the inverse hyperbolic functions in
MathML 2.0. The inverse trigonometric functions have prefix "arc"

     sin -> arcsin, cos -> arccos, ...

The reason is that they return the angle (measured by arc on unit sphere).
That interpretation is not valid for hyperbolic functions. Their inverses
are (historically) related to area. Therefore the prefix for inverse
hyperbolic functions is "ar" (not "arc"):

     sinh -> arsinh, cosh -> arcosh, ...

or

     sh -> arsh, ch  -> arch, ...

One can double check it with reputable  sources such as the  famous
"Handbook of Mathematical Functions" by M. Abramowitz and I. Stegun.

Regrettably, the incorrect naming somehow got its way to software
engineering (for instance  Mathematica uses ArcSinh, ArcCosh, etc.) and it
is spreading. I have already seen some math books using it. I suggest the
return to traditional, correct, and meaningful names for inverse
hyperbolic functions before it is to late.:-)

-- Leszek Sczaniecki
Received on Saturday, 29 April 2000 09:39:47 GMT

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