共50条信息
设二次函数\(f(x)=ax^{2}+bx+c\),函数\(F(x)=f(x)-x\)的两个零点为\(m\),\(n(m < n)\).
\((1)\)若\(m=-1\),\(n=2\),求不等式\(F(x) > 0\)的解集;
\((2)\)若\(a > 0\),且\(0 < x < m < n < \dfrac{{1}}{a}\),比较\(f(x)\)与\(m\)的大小.
已知\(f(x)\)是定义在\(R\)上的奇函数,对任意两个不相等的正数\(x_{1}\)、\(x_{2}\)都有\(\dfrac{{x}_{2}f({x}_{1})−{x}_{1}f({x}_{2})}{{x}_{1}−{x}_{2}} < 0 \),记\(a= \dfrac{f({4.1}^{0.2})}{{4.1}^{0.2}} \),\(b= \dfrac{f({0.4}^{2.1})}{{0.4}^{2.1}} \),\(c= \dfrac{f({\log }_{0.2}4.1)}{{\log }_{0.2}4.1} \),则\((\) \()\)
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.
定义在\(\left( 0,+\infty \right)\)上的函数\(f\left( x \right)\)的导函数\({f}{{{"}}}\left( x \right)\)满足\(\sqrt{x}{f}{{{"}}}\left( x \right) < \dfrac{1}{2}\),则下列不等式中,一定成立的是( )
将离心率为\(e_{1}\)的双曲线\(C_{1}\)的实半轴长\(a\)和虚半轴长\(b(a\neq b)\)同时增加\(m(m > 0)\)个单位长度,得到离心率为\(e_{2}\)的双曲线\(C_{2}\),则
设不等式\(0 < \left| x+2 \right|-\left| 1-x \right| < 2\)的解集为\(M\),\(a\),\(b∈M\)
\((1)\)证明:\(\left| a+\dfrac{1}{2}b \right| < \dfrac{3}{4}\);
\((2)\)比较\(|4ab-1|\)与\(2|b-a|\)的大小,并说明理由.
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