2.
已知向量\( \overrightarrow{m}=(2,\sin α)\),\( \overrightarrow{n}=(\cos α,-1)\),其中\(α∈(0, \dfrac {π}{2})\),且\( \overrightarrow{m}⊥ \overrightarrow{n}\).
\((1)\)求\(\sin 2α\)和\(\cos 2α\)的值;
\((2)\)若\(\sin (α-β)= \dfrac { \sqrt {10}}{10}\),且\(β∈(0, \dfrac {π}{2})\),求角\(β\).