共50条信息
已知正实数\(x\),\(y\)满足\(x+y+3=xy\),若对任意满足条件的\(x\),\(y\),都有\({{(x+y)}^{2}}-a(x+y)+1\geqslant 0\)恒成立,则实数\({a}\)的取值范围为________
设函数\(f\left( x \right)={\ln }x\),若\(a,b\)是两个不相等的正数且\(p=f\left( \sqrt{ab} \right),q=f\left( \dfrac{a+b}{2} \right)\) \(r=\dfrac{1}{2}f\left( \dfrac{{{a}^{2}}+{{b}^{2}}}{2} \right)\) \(v=\dfrac{1}{2}\left[ f\left( a \right)+f\left( b \right) \right]\),则下列关系式中正确的是\((\) \()\)
设函数\(f\left( x \right)={{x}^{2}}+aIn\left( 1+x \right)\)有两个极值点\(x_{1}\),\(x_{2}\),且\({{x}_{1}} < {{x}_{2}}\)
\((I)\)求\(a\)的取值范围,并讨论\(f\left( x \right)\)的单调性;
\((II)\)证明:\(f\left( {{x}_{2}} \right) > \dfrac{1-2In2}{4}\)
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