1.
如图,半径为\(1\),圆心角为\( \dfrac {3π}{2}\)的圆弧\( \hat AB\)上有一点\(C\).
\((1)\)若\(C\)为圆弧\(AB\)的中点,点\(D\)在线段\(OA\)上运动,求\(| \overrightarrow{OC}+ \overrightarrow{OD}|\)的最小值;
\((2)\)若\(D\),\(E\)分别为线段\(OA\),\(OB\)的中点,当\(C\)在圆弧\( \hat AB\)上运动时,求\( \overrightarrow{CE}⋅ \overrightarrow{CD}\)的取值范围.