4.
设\(A,B\)为双曲线\(\dfrac{{{x}^{2}}}{{{a}^{2}}}-\dfrac{{{y}^{2}}}{{{b}^{2}}}=\lambda (\lambda \ne 0)\)同一条渐近线上的两不同点,\(\overrightarrow{m}=(1,0),\ |\overrightarrow{AB}|=6,\dfrac{\overrightarrow{AB}\cdot \overrightarrow{m}}{|\overrightarrow{m}|}=3\),则双曲线的离心率为______________