\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
Find the principal argument of the complex number \(z = \frac{3\sqrt{3}}{2} +i\frac{3}{2}\). (i.e., the argument in the interval \((-\pi, \pi]\)).
\(\arg(z)=\)