On Wed, Sep 05, 2007 at 10:37:18 +1000, Andrew Maclean <andrew.amaclean@xxxxxxxxx> 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. ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
