From: Harry Ohlsen <harryo@...>
Date: 2001-12-06T14:52:21+09:00
Subject: [ruby-talk:27636] Re: Help! acos, asin - where?

In article <qksP7.154769$fm5.30633687@typhoon.southeast.rr.com>, "Thomas
R. Corbin" <tc@clark.net> wrote:

> I found the Math::atan2 (why 2?) method, but haven't figured out how to
> do acos or asin.   I'm sure I'm missing something simple, but I'm
> stumped.
> 
>         Thanks for your help,
>         Tom Corbin

For some reason, the standard maths libraries tend to only include atan.
My guess is that they intend you to just do the appropriate fiddle to
turn your acos/asin problem into an atan one.

I guess one can do something with "tan^2  + 1 = sec^2".

No idea why they don't just include those calculations in the library,
though.