
如图,\(AD/\!/BC\)且\(AD=2BC\),\(AD⊥CD\),\(EG/\!/AD\)且\(EG=AD\),\(CD/\!/FG\)且\(CD=2FG\),\(DG⊥\)平面\(ABCD\),\(DA=DC=DG=2.\)
\((1)\)若点\(M\)为\(CF\)的中点,点\(N\)为\(EG\)的中点,点\(P\)为线段\(DG\)上动点,且平面\(MNP/\!/\)平面\(CDE\),求\(\dfrac{GP}{GD}\)的值;
\((2)\)求二面角\(E-BC-F\)的正弦值.