已知:如图,经过点\(C(5,0)\)的直线\(y=\left( 1-k \right)\bullet {{x}^{\left| k-0.5 \right|}}+b\)交\(y\)轴的正半轴于\(D\)点.
\((1)\)求直线\(CD\)的解析式;
\((2)\)点\(B\)为线段\(CD\)上一点,连接\(OB\),过\(O\)点作\(OA⊥OB\)交直线\(CD\)于点\(A\),若\(OA=OB\),求点\(A\)的坐标;
\((3)\)在\((2)\)的条件下,将\(\triangle COD\)绕坐标原点\(O\)逆时针方向旋转\(90^{\circ}\)得到\(\triangle EOF\).
\(①\)判断点\(A\)是否在直线\(EF\)上,并说明理由;
\(②G\)点是线段\(BD(\)含端点\()\)上一动点,直线\(FG\)的解析式为\(y=mx+n\),试探究\(n\)和\(m\)之间的关系,并求出系数\(m\)的取值范围.