atan2(x,x)



maxima-bounces at math.utexas.edu wrote on 11/18/2008 08:02:48 AM:

> By the way, I don't think it is silly to check the sign for atan2(x,x); 
if x
> is positive, the result is %pi/4, but if x is negative, we're in the 
third
> quadrant and the result is -3*%pi/4, isn't it?


Sure, if x  < 0, atan2(x,x) = -3 * %pi / 4; if x > 0, atan2(x,x) = %pi/4. 
So either
the question is needed or Maxima needs to return a conditional statement.

What I think is silly is the fact that Maxima does an asksign for 
atan2(x,x), but
not for atan2(c * x, x), where c is a real number (say c = sqrt(3)). 
Surely Maxima 
should either do an asksign for both atan2(x,x) and atan2(c * x, x), or 
not do an 
asksign for both atan2(x,x) and atan2(c * x, x).

Barton