Molecular shape of SF₄, CF₄ and XeF₄ are

The hybridisation of atomic orbitals of nitrogen in $$NO_2^+$$, $$NO_3^-$$ and $$NH_4^+$$ are

Let $$f\left( \theta \right) = \sin \theta \left( {\sin \theta + \sin 3\theta } \right)$$. Then $$f\left( \theta \right)$$ is

If $$\arg \left( z \right) < 0,$$ then $$\arg \left( { - z} \right) - \arg \left( z \right) = $$