The interval in which the function $f ( x ) = x ^ { x } , x > 0$, is strictly increasing is\\
(1) $\left( 0 , \frac { 1 } { e } \right]$\\
(2) $( 0 , \infty )$\\
(3) $\left[ \frac { 1 } { e } , \infty \right)$\\
(4) $\left[ \frac { 1 } { e ^ { 2 } } , 1 \right)$