Q72. If the function $f ( x ) = \frac { \sin 3 x + \alpha \sin x - \beta \cos 3 x } { x ^ { 3 } } , x \in \mathbf { R }$, is continuous at $x = 0$, then $f ( 0 )$ is equal to : (1) 2 (2) - 2 (3) 4 (4) - 4
Q72. If the function $f ( x ) = \frac { \sin 3 x + \alpha \sin x - \beta \cos 3 x } { x ^ { 3 } } , x \in \mathbf { R }$, is continuous at $x = 0$, then $f ( 0 )$ is equal to :\\
(1) 2\\
(2) - 2\\
(3) 4\\
(4) - 4