If $2 \sin ^ { 3 } x + \sin 2 x \cos x + 4 \sin x - 4 = 0$ has exactly 3 solutions in the interval $\left[ 0 , \frac { \mathrm { n } \pi } { 2 } \right] , \mathrm { n } \in \mathrm { N }$, then the roots of the equation $x ^ { 2 } + n x + ( n - 3 ) = 0$ belong to :\\
(1) $( 0 , \infty )$\\
(2) $( - \infty , 0 )$\\
(3) $\left( - \frac { \sqrt { 17 } } { 2 } , \frac { \sqrt { 17 } } { 2 } \right)$\\
(4) $Z$