优优班--学霸训练营 > 知识点挑题
全部资源
          排序:
          最新 浏览

          50条信息

            • 1.

              已知\(a,b,c,d,e,f,g\)是和为\(1\)的非负实数, \(M=max\{a+b+c, b+c+d,c+d+e,d+e+f,e+f+g\}\)则\(M\)的最小值为                                      \((\)   \()\)

              A.\(\dfrac{1}{2}\)
              B.\(\dfrac{1}{3}\)
              C.\(\dfrac{1}{4}\)
              D.\(\dfrac{1}{5}\)
            • 2.

              设实数\(a\),\(b\),\(c\)满足\(\begin{cases} & b+c\leqslant 4a \\ & c-b\geqslant 0 \\ & b\geqslant a > 0 \end{cases}.\)但不满足\({{(a+b)}^{2}}+{{\left( a+c \right)}^{2}}={{\left( ar \right)}^{2}}\left(r > 0\right) \),则\(r\)的取值范围是__________________.

            • 3.

              已知\(a > 0\),\(b > 0\),且\(a\neq b\),比较\(\dfrac{{{a}^{2}}}{b}+\dfrac{{{b}^{2}}}{a}\)与\(a+b\)的大小.

            • 4.

              选修\(4-5\):不等式选讲

              已知\(a > 0 \),\(b > 0 \),函数\(f(x)=|x+a|+|x-b| \)的最小值为\(4\).

              \((\)Ⅰ\()\)求\(a+b \)的值;

              \((\)Ⅱ\()\)求\( \dfrac{1}{4}{a}^{2}+ \dfrac{1}{9}{b}^{2} \)的最小值.

            • 5. 不等式选讲 已知\(a\),\(b\),\(c∈R^{+}\),求证:
              \((1)(ab+a+b+1)(ab+ac+bc+c^{2})\geqslant 16abc\)
              \((2) \dfrac{b+c-a}{a} + \dfrac{c+a-b}{b} + \dfrac{a+b-c}{c} \geqslant 3\).
            • 6.

              \((1)\)命题“\(\forall x\in R\),\({{x}^{2}}+4x+5 > 0\)”的否定是                         

              \((2).\)已知直线\(l:2x-y-2=0\)与抛物线\(C:{{y}^{2}}=8x\)交于\(A\),\(B\)两点,则\(\left| AB \right|=\)       

              \((3).\)已知实数\(a,b,c\in R\),则“\(a > b\)”是“\(a{{c}^{2}} > b{{c}^{2}}\)”的                 条件.

              \((4).\)若椭圆\(\dfrac{{{x}^{2}}}{{{a}^{2}}}+\dfrac{{{y}^{2}}}{{{b}^{2}}}=1(a > b > 0)\)离心率为\(\dfrac{\sqrt{2}}{2}\),则双曲线\(\dfrac{{{x}^{2}}}{{{a}^{2}}}-\dfrac{{{y}^{2}}}{{{b}^{2}}}=1\)的离心率为    

              \((5).\)已知椭圆\(C\)的方程为\(\dfrac{{{x}^{2}}}{{{a}^{2}}}+\dfrac{{{y}^{2}}}{{{b}^{2}}}=1\left( a > b > 0 \right),{{F}_{1}},{{F}_{2}}\)为其左、右焦点,\(e\)为离心率,\(P\)为椭圆上一动点,则有如下命题:

                \(①\)当\(0 < e < \dfrac{\sqrt{2}}{2}\)时,使\(\Delta P{{F}_{1}}{{F}_{2}}\)为直角三角形的点\(P\)有且只有\(4\)个;

                \(②\)当\(e=\dfrac{\sqrt{2}}{2}\)时,使\(\Delta P{{F}_{1}}{{F}_{2}}\)为直角三角形的点\(P\)有且只有\(6\)个;

                \(③\)当\(\dfrac{\sqrt{2}}{2} < e < 1\)时,使\(\Delta P{{F}_{1}}{{F}_{2}}\)为直角三角形的点\(P\)有且只有\(8\)个.

                其中真命题的有          \((\)请写出所有真命题的序号\()\).

            • 7.

              \((1)\)已知\(-1 < \)\(a\)\( < \)\(b\)\( < 2\),则\(a\)\(-\)\(b\)的范围是__________.

              \((2)\)不等式:\(|\)\(x\)\(-1|+2\)\(x\)\( > 4\)的解集是______________.

              \((3)\)圆\(C\):\(ρ=-4\)\(\sin \)\(θ\)上的动点\(P\)到直线\(l\):\(ρ\)\(\sin \)\((θ+ \dfrac{π}{4} )= \sqrt{2} \)的最短距离为______.

              \((4)\)参数方程\(\begin{cases}x=\cos θ \\ y=1+\cos θ\end{cases} (θ∈R)\)化为普通方程是___________.

            • 8.

              已知\(x\)\(∈R\),使得关于\(x\)的不等式\(|x-\)\(1\)\(|-|x-\)\(2\)\(|\)\(\geqslant \)\(t\)恒成立

              \((1)\)求满足条件的实数\(t\)所构成的集合\(T\)\(;\)

              \((2)\)若\(m > \)\(1\),\(n > \)\(1\),且对于\(∀\)\(t\)\(∈\)\(T\),不等式\(\log _{3}\)\(m\)\(·\log _{3}\)\(n\)\(\geqslant \)\(t\)恒成立,试求\(m+n\)的最小值

            • 9.

              已知椭圆\(E:\dfrac{{{x}^{2}}}{{{a}^{2}}}+\dfrac{{{y}^{2}}}{{{b}^{2}}}=1(a > b > 0)\)的右焦点为\(F\),短轴的一个端点为\(M\),直线\(l\):\(3x-4y=0\)交椭圆\(E\)于\(A\),\(B\)两点\(.\)若\(|AF|+|BF|=4\),点\(M\)到直线\(l\)的距离不小于\(\dfrac{4}{5}\),则椭圆\(E\)的离心率的取值范围是

              A.\((0,\dfrac{\sqrt{3}}{2}]\)
              B.\((0,\dfrac{3}{4}]\)
              C.\([\dfrac{\sqrt{3}}{2},1)\)
              D.\([\dfrac{3}{4},1)\)
            • 10.
              设\(a\)、\(b\)是正实数,以下不等式:\(① \sqrt {ab} > \dfrac {2ab}{a+b}\);\(②a > |a-b|-b\);\(③a^{2}+b^{2} > 4ab-3b^{2}\);\(④ab+ \dfrac {2}{ab} > 2\)恒成立的序号为\((\)  \()\)
              A.\(①③\)
              B.\(①④\)
              C.\(②③\)
              D.\(②④\)
            0/40

            进入组卷