3.
\((1)\)若\({a}^{2}+{b}^{2}=0 \), 则\(a=0\)_____\(b=0\); \(((\)用适当的逻辑联结词“且”“或”“非” \()\)
\((2)\)已知函数\(f(x)={e}^{x}\sin x \),则\(f{{'}}(0)=\) ______ .
\((3)\)设\(l\),\(m\)是两条不同的直线,\(α,β \)是两个不重合的平面,给出下列四个命题:
\(①\)若\(α/\!/β,l⊥α \),则\(l⊥β \);
\(②6\)若\(l/\!/m,l⊂α \),则\(α/\!/β \);
\(③\)若\(m⊥αl⊥m \),则\(l/\!/α \);
\(④\)若\(l/\!/α,l⊥β \),则\(α⊥β \).
其中真命题的序号有______ \((\)写出所有正确命题的序号\()\)
\((4)\)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________.