On Wed, Sep 05, 2007 at 10:37:18 +1000,
Andrew Maclean <andrew.amaclean@gmail.com> 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
Aren't those two statements sayiong the same thing?
You've just switched the names 'x' and 'y' and not changed their relationships.
>
>
> 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)).
In this example you switched things around part way thorugh. atan2(1,2)
is the atan of (1/2), not atan(2/1) as used at the beginning of the example.
> So it must be degrees(atan2(y,x))=degrees(atan2(2,1))=63.4.
