Given that $0 < x < \frac { \pi } { 2 }$,
$$\frac { \sec ( x ) - 1 } { 2 } = \frac { 3 } { \sec ( x ) + 1 }$$
the equality holds.\
Accordingly, what is the value of $\tan ( x )$?\
A) $\sqrt { 2 }$\
B) $\sqrt { 3 }$\
C) $\sqrt { 5 }$\
D) $\sqrt { 6 }$\
E) $\sqrt { 7 }$