carg (?) bug



Hi,

I make complex number in exponential form :
R:16;
T:1/3;
Z:R*exp(T*%i*2*%pi);

output is :
16*((sqrt(3)*%i)/2-1/2)

Then check radius :

r:abs(Z)
  16

it is good , but carg :

(%i6) t:carg(Z)
(%o6) (2*%pi)/3

It gives 2/3 not 1/3 .
Is it a bug ?

Adam

PS On image on page :

http://fraktal.republika.pl/q_iteration.html
it is a point z2 and it is on ray 1/3 not 2/3

======== code ==============
R:16;
T:1/3;
Z:R*exp(T*%i*2*%pi);
r:abs(Z);
t:carg(Z);
z:r*exp(t*%i*2*%pi);

====== output ==============
(%i2) R:16
(%o2) 16
(%i3) T:1/3
(%o3) 1/3
(%i4) Z:R*exp(T*%i*2*%pi)
(%o4) 16*((sqrt(3)*%i)/2-1/2)
(%i5) r:abs(Z)
(%o5) 16
(%i6) t:carg(Z)
(%o6) (2*%pi)/3
(%i7) z:r*exp(t*%i*2*%pi)
(%o7) 16*%e^((4*%i*%pi^2)/3)