如图,已知平面\(ADC/\!/\)平面\(A_{1}B_{1}C_{1}\),\(B\)为线段\(AD\)的中点,\(\triangle ABC≈\triangle A_{1}B_{1}C_{1}\),四边形\(ABB_{1}A_{1}\)为正方形,平面\(AA_{1}C_{1}C\)丄平面\(ADB_{1}A_{1}\),\(A_{1}C_{1}=A_{1}A\),\(∠C_{1}A_{1}A= \dfrac {π}{3}\),\(M\)为棱\(A_{1}C_{1}\)的中点.
\((I)\)若\(N\)为线段\(DC_{1}\)上的点,且直线\(MN/\!/\)平面\(ADB_{1}A_{1}\),试确定点\(N\)的位置;
\((\)Ⅱ\()\)求平面\(MAD\)与平面\(CC_{1}D\)所成的锐二面角的余弦值.