6.
\((1)\)一同学在电脑中打出如下若干个圆\((\)图中\(●\)表示实圆,\(○\)表示空心圆\()\):\(●○●●○●●●○●●●●○●●●●●○●●●●●●○\),若将此若干个圆依次复制得到一系列圆,那么在前\(2018\)个圆中,有_______个空心圆.
\((2)\)设\({{Z}_{1}}= i^{4} + i^{5}+ i^{6}+…+ i^{12}\),\(Z{}_{2}= i^{4} · i^{5}·i^{6}·…· i^{12}\),则\(Z_{1}\) ,\(Z{}_{2}\)关系为________________
\((3)y=f\left(x\right) \)在\(x={x}_{0} \)处可导,且\( \lim\limits_{∆x→0} \dfrac{f\left({x}_{0}-3∆x\right)-f\left({x}_{0}\right)}{∆x}=1 \),则\(f{{'}}\left({x}_{0}\right) =\) \(\_\)
\((4)\)若函数\(f(x)={{x}^{3}}-a{{x}^{2}}+4\)在\((0,2)\)内单调递减,则实数\(a\)的取值范围是___________.