3.
如图,在四棱锥\(E-ABCD\)中,\(AE\bot DE\),\(CD\bot \)平面\(ADE\),\(AB\bot \)平面\(ADE\),\(CD=DA=6\),\(AB=2\),\(DE=3\).
\((\)Ⅰ\()\)求棱锥\(C-ADE\)的体积;
\((\)Ⅱ\()\)求证:平面\(ACE\bot \)平面\(CDE\);
\((\)Ⅲ\()\)在线段\(DE\)上是否存在一点\(F\),使\(AF{/\!/}\)平面\(BCE\)?若存在,求出\(\dfrac{EF}{ED}\)的值;若不存在,说明理由.