5.
\((1)\)一个正方体的体积为\(8c{{m}^{3}}\),这个正方体的外接球的体积为___________\(c{{m}^{3}}\).
\((2)\)集合\(A=\{x|{{x}^{2}}-3x-10\leqslant 0\}\),\(B=\{x|m+1⩽x⩽2m−1\} \),若\(A\bigcap B=B\),则实数\(a\)的取值范围是_____.
\((3)\)已知函数\(f\left(x\right)=\begin{cases}\left(2a-1\right)x+7a-2, & x < 1 \\ {a}^{x}, & x\geqslant 1\end{cases} \)在\(R\)上单调递减,则实数\(a\)的取值范围是___________.
\((4)\)已知平面\(\alpha ,\beta \),直线\(m,n\),且\(m\bot \alpha \),\(n\subseteq \beta \)给出下列四中说法:
\(①\)若\(\alpha /\!/\beta \),则\(m\bot n\);
\(②\)若\(m\bot n\),则\(\alpha /\!/\beta \);
\(③\)若\(m/\!/n\),则\(\alpha \bot \beta \);
\(④\)若\(\alpha \bot \beta \),则\(m/\!/n\);
以上说法正确的有________________.