9.
已知向量\( \overrightarrow{a}=(\cos x+\sin x,1)\),\( \overrightarrow{b}=(\cos x+\sin x,-1)\)函数\(g(x)=4 \overrightarrow{a}⋅ \overrightarrow{b}\).
\((1)\)求函数\(g(x)\)在\([ \dfrac {π}{12}, \dfrac {π}{3}]\)上的值域;
\((2)\)若\(x∈[0,2016π]\),求满足\(g(x)=0\)的实数\(x\)的个数;
\((3)\)求证:对任意\(λ > 0\),都存在\(μ > 0\),使\(g(x)+x-4 < 0\)对\(x∈(-∞,λμ)\)恒成立.