6.
如图,在\(Rt\triangle AOB\)中,\(∠AOB=90^{\circ}\),\(0A=OB=2\),点\(D\),\(E\)分别是\(OA\),\(OB\)边的中点,若正方形\(ODCE\)绕点\(O\)按逆时针方向旋转,得到正方形\(OD_{1}C_{1}E_{1}\),记旋转角为\(α\).
\((1)\)如图\(①\),当\(α=90^{\circ}\)时,线段\(AD_{1}\)的长度是________,线段\(BE_{1}\)的长度是________;
\((2)\)如图\(②\),当\(α=135^{\circ}\)时,求证:\(AD_{1}=BE_{1}\),且\(AD_{1}⊥BE_{1}\);
\((3)\)若直线\(AD_{1}\)与直线\(BE_{1}\)相交于点\(M\),填空:
\(①\)线段\(MC\)的长为________;
\(②\)点\(M\)到直线\(OA\)的距离的最大值为________.