1. The function $\sqrt[x]{x}, \: (x>0)$, has the global maxima at $x=e$
2. The function $\sqrt[x]{x}, \: (x>0)$, has the global minima at $x=e$
3. The function $x^3$ has neither global minima nor global maxima
4. The function $\mid x \mid$ has the global minima at $x=0$