10.
\((1)\)
设\(x\)、\(y\)满足约束条件\(\begin{cases}\begin{matrix}x\geqslant 0 \\ x\geqslant y\end{matrix} \\ 2x-y\leqslant 1\end{cases} \)若目标函数为\(z=2x+4y\),则\(z\)的最大值为____.
\((2)\) 已知锐角\(\triangle ABC\)的外接圆半径为\( \dfrac{ \sqrt{3}}{3}BC \),且\(AB=3\),\(AC=4\),则\(BC=\) .
\((3)\) 已知函数\(f(x)=({2}^{x}− \dfrac{1}{{2}^{x}})⋅{x}^{3} \),且\(f(x−2) > 0 \),则实数\(x \)的取值范围是_____\(.\)
\((4)\) 已知函数\(f(x)= \dfrac{1}{4} x^{2}+ \dfrac{1}{2} x+a(x < 0)\),\(g(x)=\ln x(x > 0)\),其中\(a∈R.\)若存在\(A\)点、\(B\)点使得\(f(x)\)的图象在点\(A(x_{1},f(x_{1}))\)处的切线与\(g(x)\)的图象在点\(B(x_{2},f(x_{2}))\)处的切线重合,则\(a\)的取值范围为_____\(.\)