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. 已知函数\(f(x)=\ln (1+x)- \dfrac {x(1+λx)}{1+x}\),若\(x\geqslant 0\)时,\(f(x)\leqslant 0\),则\(λ\)的最小值为\((\)  \()\)
              A.\(0\)
              B.\( \dfrac {1}{2}\)
              C.\(1\)
              D.\(2\)
            • 4. 已知\(f(x)\)定义域为\((0,+∞)\),\(f′(x)\)为\(f(x)\)的导函数,且满足\(f(x) < -xf′(x)\),则不等式\(f(x+1) > (x-1)·f(x^{2}-1)\)的解集是\((\)    \()\)
              A.\((0,1)\)              
              B.\((1,+∞)\)                
              C.\((1,2)\)                
              D.\((2,+∞)\)
            • 5. 已知\(0 < a < b\),若函数\(f(x)=2x+ \dfrac {1}{x}\)在\([a,b]\)上单调递增,则对于任意\(x_{1}\),\(x_{2}∈[a,b]\),且\(x_{1}\neq x_{2}\),使\(f(a)\leqslant \dfrac {g(x_{1})-g(x_{2})}{x_{1}-x_{2}}\leqslant f(b)\)恒成立的函数\(g(x)\)可以是\((\)  \()\)
              A.\(g(x)=1- \dfrac {1}{x^{2}}\)
              B.\(g(x)=x^{2}+\ln x-2\)
              C.\(g(x)=-2x- \dfrac {1}{x}\)
              D.\(g(x)=e^{x}(2x+ \dfrac {1}{x})\)
            • 6.
              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.\(f(1) < 2f( \dfrac {π}{6})⋅\sin 1\)
            • 7.

              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.\(c < a < b \)
            • 8.
              已知函数\(y=f(x)\)是定义在实数集\(R\)上的奇函数,且当\(x∈(-∞,0)\)时,\(xf′(x) < f(-x)\)成立\((\)其中\(f′(x)\)是\(f(x)\)的导函数\()\),若\(a= \sqrt {3}f( \sqrt {3})\),\(b=(\lg 3)f(\lg 3),c=(\log _{2} \dfrac {1}{4})f(\log _{2} \dfrac {1}{4})\),则\(a\),\(b\),\(c\)的大小关系是\((\)  \()\)
              A.\(c > a > b\)
              B.\(c > b > a\)
              C.\(a > b > c\)
              D.\(a > c > b\)
            • 9. 已知函数f(x)=x3-3x-1,g(x)=2x-a,若对任意x1∈[0,2],存在x2∈[0,2]使|f(x1)-g(x2)|≤2,则实数a的取值范围(  )
              A.[1,5]
              B.[2,5]
              C.[-2,2]
              D.[5,9]
            • 10. 若曲线C1:y=x2与曲线C2:y=aex(a>0)至少存在两个交点,则a的取值范围为(  )
              A.[,+∞)
              B.(0,]
              C.[,+∞)
              D.(0,]
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