Investigate the stability of:

(i) the equilibrium points of the equation

$$\frac{d y}{d t}=\left(y^{2}-4\right) \tan ^{-1}(y)$$

(ii) the constant solutions $\left(u_{n+1}=u_{n}\right)$ of the discrete equation

$$u_{n+1}=\frac{1}{2} u_{n}^{2}\left(1+u_{n}\right)$$