8.
若锐角\(α\)、\(β\)满足\((1+ \sqrt{3} \)\(\tan \)\(α)(1+ \sqrt{3} \)\(\tan \)\(β)=4\),则\(α+β= \)______.
已知\(2 \overset{→}{a} - \overset{→}{b} =(-1, \sqrt{3} )\),\( \overset{→}{c} =(1, \sqrt{3} )\)且\( \overset{→}{a} · \overset{→}{c} =3\),\(| \overset{→}{b} |=4\),则\( \overset{→}{b} \)与\( \overset{→}{c} \)的夹角为 ______.
已知\(x\)\(∈R\),向量\( \overset{→}{AB} =(-1,x+2)\),\( \overset{→}{CD} =(x,1)\),则在\( \overset{→}{AB} \)方向上的投影的最大值为 ______.
已知函数
\(f\)\(( \)
\(x\)\()=\)
\(\sin \)\({\,\!}^{2}\)
\(x\)\(+\)
\(\sin x\cos x\)\(- \dfrac{1}{2} \),下列结论中:
\(①\)函数
\(f\)\(( \)
\(x\)\()\)关于
\(x\)\(= \dfrac{π}{8} \)对称;
\(②\)函数
\(f\)\(( \)
\(x\)\()\)关于\((- \dfrac{π}{8} ,0)\)对称;
\(③\)函数
\(f\)\(( \)
\(x\)\()\)在\((0, \dfrac{π}{8} )\)是增函数,
\(④\)将
\(y\)\(= \dfrac{ \sqrt{2}}{2} \)
\(\cos \)\(2\)
\(x\)的图象向右平移\( \dfrac{3π}{8} \)可得到
\(f\)\(( \)
\(x\)\()\)的图象.
其中正确的结论序号为 ______.