7.
\((1)\)命题“若\(x\geqslant 1\),则\({{x}^{2}}-4x+2\geqslant -1\)”的否命题为___________________________
\((2)\)复数\(z\)满足\(\left( z+2{i} \right){i}=3-{i}(i\)为虚数单位\()\),则\(\left| z \right|=\)_________.
\((3)\)若\(a\),\(b\),\(c\)都是正数,且\(a+b+c=2\),则\(\dfrac{4}{a+1}+\dfrac{1}{b+c}\)的最小值为____________
\((4)\)观察下列等式:
\(1^{3}=1\),
\(1^{3}+2^{3}=9\),
\(1^{3}+2^{3}+3^{3}=36\),
\(1^{3}+2^{3}+3^{3}+4^{3}=100\),
\(…\)
照此规律,第\(n\)个等式可为:\({{1}^{3}}+{{2}^{3}}+{{3}^{3}}+\cdots +{{n}^{3}}=\)________________