Re: Documentation fix regarding atan2 - Mailing list pgsql-general

From Andrew Maclean
Subject Re: Documentation fix regarding atan2
Date
Msg-id e7ddbec60709161702r725038aat98cdb99e8db211b0@mail.gmail.com
Whole thread Raw
In response to Re: Documentation fix regarding atan2  (Bruce Momjian <bruce@momjian.us>)
List pgsql-general
Thanks.

On 9/15/07, Bruce Momjian <bruce@momjian.us> wrote:

Change made.  Thanks.  Your documentation changes can be viewed in five
minutes using links on the developer's page,
http://www.postgresql.org/developer/testing.

---------------------------------------------------------------------------


Andrew Maclean wrote:
> In Table 9.4 of the documentation atan2 is described as follows:
>   atan2(*x*, *y*) inverse tangent of *x*/*y*
>
> I am sure it should read as:
>   atan2(*y*, x) inverse tangent of y/x
>
> This looks to be the standard C++/c atan2(y,x) function.
>
> You can easily test this:
> If y = 2, x = 1, then degrees(atan(y/x)) =63.4 but if we proceed according
> to the documentation; degrees(atan2(x,y))=degrees(atan2(1,2))= 25.6 which is
> not the same as degrees(atan(y/x)).
> So it must be degrees(atan2(y,x))=degrees(atan2(2,1))=63.4.
>
>
> Thanks
>    Andrew
>
> --
> ___________________________________________
> Andrew J. P. Maclean
> Centre for Autonomous Systems
> The Rose Street Building J04
> The University of Sydney  2006  NSW
> AUSTRALIA
> Ph: +61 2 9351 3283
> Fax: +61 2 9351 7474
> URL: http://www.acfr.usyd.edu.au/
> ___________________________________________

--
Bruce Momjian  <bruce@momjian.us >          http://momjian.us
EnterpriseDB                               http://www.enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +

---------------------------(end of broadcast)---------------------------
TIP 4: Have you searched our list archives?

              http://archives.postgresql.org/



--
___________________________________________
Andrew J. P. Maclean
Centre for Autonomous Systems
The Rose Street Building J04
The University of Sydney  2006  NSW
AUSTRALIA
Ph: +61 2 9351 3283
Fax: +61 2 9351 7474
URL: http://www.acfr.usyd.edu.au/
___________________________________________

pgsql-general by date:

Previous
From: Jeff Davis
Date:
Subject: Re: pg_standby observation
Next
From: Ow Mun Heng
Date:
Subject: New/Custom DataType - Altering definition / seeing definition in pgAdmin3