2.
\((1)\) 已知平面向量\(\overrightarrow{a},\overrightarrow{b}\)是非零向量,\(|\overrightarrow{a}|=2\),\(\overrightarrow{a}\bot (\overrightarrow{a}+2\overrightarrow{b})\),则向量\(\overrightarrow{b}\)在向量\(\overrightarrow{a}\)方向上的投影为____.
\((2)\)等比数列\(\left\{ {{a}_{n}} \right\}\)的各项均为实数,其前\(n\)项的和为\({{S}_{n}}\),已知\({{S}_{3}}=\dfrac{7}{4}\),\({{S}_{6}}=\dfrac{63}{4}\),则\({{S}_{9}}=\)_______.
\((3)\)已知点\({{F}_{1}},{{F}_{2}}\)分别为椭圆\(C:\dfrac{{{x}^{2}}}{{{a}^{2}}}+\dfrac{{{y}^{2}}}{{{b}^{2}}}=1(a > b > 0)\)的左、右焦点,点\(P\)为椭圆上一点,且\(\overrightarrow{{P}{{{F}}_{1}}}\cdot \overrightarrow{{P}{{{F}}_{2}}}=0\),\(\angle {P}{{{F}}_{{2}}}{{{F}}_{{1}}}=5\angle {P}{{{F}}_{{1}}}{{{F}}_{{2}}}\),则椭圆\(C\)的离心率是_________.
\((4)\)已知函数\(f(x)=({{x}^{2}}-1)({{x}^{2}}+ax+b)\)的图象关于直线\(x=3\)对称,则函数\(f(x)\)的值域为_______.