\((1)\)抛物线\({{y}^{2}}=ax(a > 0)\)上的点\(P(\dfrac{3}{2},{{y}_{0}})\)到焦点\(F\)的距离为\(2\),则\(a=\)_________.
\((2)\)已知递减等差数列\(({{a}_{n}})\)中,\({{a}_{3}}=-1,{{a}_{4}}\)为\({{a}_{1}},-{{a}_{6}}\)等比中项,若\({{S}_{n}}\)为数列\(({{a}_{n}})\)的前\(n\)项和,则\({{S}_{7}}\)的值为_________.
\((3)\)在四面体\(S-ABC\)中,\(AB\bot BC,AB=BC=\sqrt{2},SA=SC=2\),二面角\(S-AC-B\)的余弦值是\(-\dfrac{\sqrt{3}}{3}\),则该四面体的外接球的表面积是_________.
\((4)\)设函数\(f(x)=\dfrac{{{x}^{2}}+1}{x},g(x)=\dfrac{x}{{{e}^{x}}},\)对任意\({{x}_{1}},{{x}_{2}}\in (0,+\infty ),\)不等式\(\dfrac{g({{x}_{1}})}{k}\leqslant \dfrac{f({{x}_{2}})}{k+1}\)恒成立,则正数\(k\)的取值范围是_________.