共50条信息
若实数\(x\),\(y\)满足\(x > y > 0\),且\(\log _{2}x+\log _{2}y=1\),则\(\dfrac{x^{2}{+}y^{2}}{x\mathrm{{-}}y}\)的最小值为____\(.\)
已知\(x\),\(y\)是满足\(2x+y=20\)的正数,则\(\lg x+\lg y\)的最大值为________.
正项等比数列\(\{ a_{n}\}\)中的\(a_{1}\),\(a_{4033}\)是函数\(f(x)=\dfrac{1}{3}{{x}^{3}}-4{{x}^{2}}+6x-3\)的极值点,则\(\log_{6}a_{2017}{=}(\) \()\)
已知数列\(\{a_{n}\}\)满足\(\log _{3}a_{n}+1=\log _{3}a_{n+1}(n∈N*)\)且\(a+a_{4}+a_{6}=9\),且\({{\log }_{\frac{1}{3}}}({{a}_{5}}+{{a}_{7}}+{{a}_{9}})\)的值是\((\) \()\)
已知\(a+{{a}^{-1}}=\dfrac{5}{2}(a > 1)\).
\((1)\)求下列各式的值:\((\)Ⅰ\(){{a}^{-\frac{1}{2}}}+{{a}^{\frac{1}{2}}}\);\((\)Ⅱ\(){{a}^{\frac{3}{2}}}+{{a}^{-\frac{3}{2}}}\);
\((2)\)已知\(2\lg (x-2y)=\lg x+\lg y\),求\({{\log }_{a}}\dfrac{y}{x}\)的值.
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