The minimum value of $f ( x ) = a ^ { a ^ { x } } + a ^ { 1 - a ^ { x } }$, where $a , x \in R$ and $a > 0$, is equal to: (1) $a + 1$ (2) $2 a$ (3) $a + \frac { 1 } { a }$ (4) $2 \sqrt { a }$
The minimum value of $f ( x ) = a ^ { a ^ { x } } + a ^ { 1 - a ^ { x } }$, where $a , x \in R$ and $a > 0$, is equal to:\\
(1) $a + 1$\\
(2) $2 a$\\
(3) $a + \frac { 1 } { a }$\\
(4) $2 \sqrt { a }$