6.
\((1)\)若\({a}^{2}+{b}^{2}=0 \), 则\(a=0\)_____\(b=0\); \(((\)用适当的逻辑联结词“且”“或”“非” \()\)
\((2)\)过抛物线\({y}^{2}=4x \)焦点\(F\)的直线交该抛物线于\(A\),\(B\)两点,若\(|AF|=3\),则\(|BF|=\)_______。
\((3)\)已知曲线\(C\):\(\begin{cases}x=2+\cos θ \\ y=\sin θ\end{cases} (t\)为参数\()\),与直线\(l\):\(\begin{cases}x=1+3t \\ y=2-4t\end{cases} (t\)为参数\()\),交于\(A\),\(B\)两点,则\(|AB|=\)__________.
\((4)\)棱长为\(2\)的正方体\(ABCD-A_{1}B_{1}C_{1}D_{1}\)中,\(E\)为棱\(CC_{1}\)的中点,点\(P\),\(Q\)分别为面\(A_{1}B_{1}C_{1}D_{1}\)和线段\(B_{1}C\)上的动点,则\(\triangle PEQ\)周长的最小值为________.