5.
\((1)\)已知向量\(\overrightarrow{a}\),\(\overrightarrow{b}\)满足\(\overrightarrow{a}=(1,\sqrt{3})\),\(|\overrightarrow{b}|=1\),且\(\overrightarrow{a}+\lambda \overrightarrow{b}=\overrightarrow{0}(λ > 0)\),则\(λ=\)________.
\((2)\)已知\(a > 0\),\(b > 0\),且\(\sqrt{3}\)为\(3^{a}\)以与\(3^{b}\)的等比中项,则\(\dfrac{ab}{4a+9b}\)的最大值为________.
\((3)\)已知四棱锥\(P-ABCD\)的底面为矩形,平面\(PBC⊥\)平面\(ABCL\),\(PE\)垂直线段\(BC\)于点\(E\),\(EC=2\),\(AB=6\),\(BC=8\),\(PE=4\),则四棱锥\(P-ABCD\)外接球的表面积是________.
\((4)\)已知平面直角坐标系中有两定点\(F_{1}(0,-2)\),\(F_{2}(0,2)\),平面中有一动点\(M\),该点使得\(\triangle MF_{1}F_{2}\)满足条件\(\sin \angle M{{F}_{1}}{{F}_{2}}=\sqrt{3}\sin \angle M{{F}_{2}}{{F}_{1}}\),则\(\overrightarrow{M{{F}_{1}}}\cdot \overrightarrow{M{{F}_{2}}}\)的取值范围是________.