Online Algebra Calculator
Many of users do not use powerful Maxima computer algebra system for systematic work, but for ad hoc algebraic calculations – equations, functions, matrixes, etc. only. To do this job, it is not useful to download the whole application from a web site.
Function: carg (<z>) Returns the complex argument of <z>. The complex argument is an angle theta in (-%pi, %pi] such that r exp (theta %i) = <z> where r is the magnitude of <z>.

carg is a computational function, not a simplifying function.
carg ignores the declaration declare (<x>, complex), and treats <x> as a real variable. This is a bug. See also abs (complex magnitude), polarform, rectform, realpart, and imagpart.
Examples:
(%i1) carg (1);
(%o1) 0
(%i2) carg (1 + %i);
%pi
(%o2) ---
4
(%i3) carg (exp (%i));
(%o3) 1
(%i4) carg (exp (%pi * %i));
(%o4) %pi
(%i5) carg (exp (3/2 * %pi * %i));
%pi
(%o5) - ---
2
(%i6) carg (17 * exp (2 * %i));
(%o6) 2(%o1) true (%i2)
realpart(((1-(%i)*sqr...
imagpart(((1-(%i)*sqr...
radcan(((1-(%i)*sqrt(...
realpart(((1-(%i)*sqr...
imagpart(((1-(%i)*sqr...
radcan(((1-(%i)*sqrt(...