\((1)\)各棱长为\(\sqrt{2}\)的正四面体的外接球与内切球体积之比为______,
\((2)\)函数\(y{=}\cos^{2}x{+}\sin x\)的最大值是______.
\((3)\)若数列\(\{ a_{n}\}\)满足\(\dfrac{1}{a_{n{+}1}}{-}\dfrac{1}{a_{n}}{=}d\),\((n{∈}N^{{*}}{,}d\)为常数\()\),则称数列\(\{ a_{n}\}\)为调和数列,已知数列\(\{\dfrac{1}{x_{n}}\}\)为调和数列,且\(x_{1}{+}x_{2}{+…+}x_{10}{=}100\),则\(x_{4}{+}x_{7}{=}\) ______ .
\((4)\)设数列\(\{ a_{n}\}\)的前\(n\)项和为\(S_{n}(n{∈}N^{{*}})\),关于数列\(\{ a_{n}\}\)有下列命题:
\({①}\)若\(\{ a_{n}\}\)既是等差数列又是等比数列,则\(a_{n}{=}a_{n{+}1}(n{∈}N^{{*}})\);
\({②}\)若\(S_{n}{=}an^{2}{+}bn\),\((a{,}b{∈}R)\),则\(\{ a_{n}\}\)是等差数列;
\({③}\)若\(S_{n}{=}1{-}({-}1)^{n}\),则\(\{ a_{n}\}\)是等比数列;
\({④}\)若\(\{ a_{n}\}\)是等比数列,则\(S_{m}\),\(S_{2m}{-}S_{m}\),\(S_{3m}{-}S_{2m}(m{∈}N^{{*}})\)也成等比数列;
其中正确的命题是______ .