如图，直三棱柱\(ABC-A_{1}B_{1}C_{1}\)中，\(∠ACB=90°\)，\(AA_{1}=3\)，\(AC=BC=2\)，点\(D\)是\(AB\)中点，点\(E\)在\(AA_{1}\)上，且\(\dfrac{AE}{A_{1}E}=\dfrac{2}{7}.\)
\((1)\)求\(C_{1}E\)与平面\(C_{1}CD\)所成角的正弦值；
\((2)\)求二面角\(C_{1}-CD-E\)的余弦值