The period of $${\sin ^2}\theta $$ is

Which one is not periodic?

z and w are two nonzero complex numbers such that $$\,\left| z \right| = \left| w \right|$$ and Arg z + Arg w =$$\pi $$ then z equals

If $$\left| {z - 4} \right| < \left| {z - 2} \right|$$, its solution is given by :