1. The problem statement, all variables and given/known data Hi all. When finding the argument of a complex number using tan(\theta) = y/x (where z = x + iy), sometimes I do not get the correct answer. I assume this is because tangent is only defined for -pi/2 to pi/2 (and from this it is periodic). So is it a good idea always to find the argument of a complex number using cosine and sine? Or am I missing something here? Thanks in advance. Regards, Niles.