优优班--学霸训练营 > 知识点挑题
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            • 1.

              若\(m∈R\),函数\(f(x)=x-\dfrac{m}{x}-2\ln x\)有两个极值点\(x_{1}\),\(x_{2}(x_{1} < x_{2})\),则\(mx_{2}\)的取值范围为\((\)    \()\)

              A.\(\left( 0,\dfrac{32}{27} \right] \)
              B.\(\left( 1,\dfrac{32}{27} \right] \)
              C.\(\left( \dfrac{32}{27},2 \right] \)
              D.\((1,2]\)
            • 2.

              如图,将直径为\(d\)的圆木锯成长方体横梁,横截面为矩形,横梁的强度同它的断面高的平方与宽\(x\)的积成正比\((\)强度系数为\(k\),\(k > 0).\)要将直径为\(d\)的圆木锯成强度最大的横梁,断面的宽\(x\)应为(    )




              A.  \(\dfrac{\sqrt{3}}{3}d\)
              B.\(\dfrac{d}{2}\)
              C.\(\dfrac{d}{3}\)
              D.\(\dfrac{\sqrt{2}}{2}d\)
            • 3.

              若不等式\(2x\ln x\geqslant -x^{2}+ax-3\)对\(x∈(0,+∞)\)恒成立,则实数\(a\)的取值范围是\((\)  \()\)

              A.\((-∞,0]\)      
              B.\([0,+ ∞)\)     
              C.\((-∞,4]\)       
              D.\([4,+ ∞)\)  
            • 4.
              已知定义在\((0, \dfrac {π}{2})\)上的函数\(f(x)\),\(f′(x)\)为其导函数,且\(f(x) < f′(x)⋅\tan x\)恒成立,则\((\)  \()\)
              A.\( \sqrt {3}f( \dfrac {π}{4}) > \sqrt {2}f( \dfrac {π}{3})\)
              B.\( \sqrt {3}f( \dfrac {π}{6}) < f( \dfrac {π}{3})\)
              C.\( \sqrt {2}f( \dfrac {π}{6}) > f( \dfrac {π}{4})\)
              D.\(f(1) < 2f( \dfrac {π}{6})⋅\sin 1\)
            • 5.
              若质点\(P\)的运动方程为\(S(t)=2t^{2}+t(S\)的单位为米,\(t\)的单位为秒\()\),则当\(t=1\)时的瞬时速度为\((\)  \()\)
              A.\(2\)米\(/\)秒
              B.\(3\)米\(/\)秒
              C.\(4\)米\(/\)秒
              D.\(5\)米\(/\)秒
            • 6.
              若\(f(x)=x^{2}-2x-4\ln x\),则\(f′(x) < 0\)的解集\((\)  \()\)
              A.\((0,+∞)\)
              B.\((0,2)\)
              C.\((0,2)∪(-∞,-1)\)
              D.\((2,+∞)\)
            • 7.
              若函数\(f(x)= \dfrac {x}{\ln x}\)在区间\((1,m)\)上递减,则\(m\)的最大值为\((\)  \()\)
              A.\(e\)
              B.\(2\)
              C.\(e^{2}\)
              D.\( \sqrt {e}\)
            • 8. 已知 \(f\)\(( \)\(x\)\()=\) \(x\ln x\)\(-\) \(ax\)\(g\)\(( \)\(x\)\()=\) \(x\)\({\,\!}^{3}-\) \(x\)\(+6\),若对任意的 \(x\)\(∈(0,+∞)\),\(2\) \(f\) \(( \)\(x\)\()\leqslant \) \(g\)\(′( \)\(x\)\()+2\)恒成立,则实数 \(a\)的取值范围为
              A.\([-2,-\)\(]\)    
              B.\([-2,+∞)\)    
              C.\((-∞,-\)\(]\)    
              D.\((-∞,-2]\)
            • 9.

              设曲线\(y\)\(=\sin \) \(x\)上任一点\((\)\(x\)\(y\)\()\)处切线的斜率为\(g\)\((\)\(x\)\()\),则函数\(y\)\(=\)\(x\)\({\,\!}^{2}\)\(g\)\((\)\(x\)\()\)的部分图像可以为(    )

              A.
              B.
              C.
              D.
            • 10.

              已知定义域为\(R\)的奇函数\(y=f(x)\)的导函数为\(y=f{{"}}(x)\),当\(x\neq 0\)时,\(f{{"}}(x)+ \dfrac{f(x)}{x} > 0 \),若\(a= \dfrac{1}{2}f( \dfrac{1}{2}),b=-2f(-2),c=-\ln 2f(\ln \dfrac{1}{2}) \),则\(a\),\(b\),\(c\)的大小关

              系正确的是\((\)    \()\)

              A.\(a < c < b\)
              B.\(b < c < a\)
              C.\(a < b < c\)
              D.\(c < a < b \)
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