共50条信息
下列各式正确的是( )
当\(0 < x\leqslant \dfrac{1}{2}\)时,\(4^{x} < \log _{a}x\),则\(a\)的取值范围是\((\) \()\)
已知复数\(z=x+yi\),其中实数\(x,y\)满足方程\({{2}^{x+y}}+i{{\log }_{2}}x-8=(1-{{\log }_{2}}y)i\),则\(z=\)__________.
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.
已知\(a+{{a}^{-1}}=5\),则\(a^{\frac{1}{2}}{-}a^{{-}\frac{1}{2}}{=}\)
求下列各式的值:
\((1){{(1.5)}^{-2}}+{{(-9.6)}^{0}}-{{(3\dfrac{3}{8})}^{-\frac{2}{3}}}+\sqrt{{{(\mathrm{ }\!\!\pi\!\!{ }-4)}^{2}}}\);
\((2){{\log }_{6}}\sqrt{27}+{{\log }_{6}}\dfrac{2}{7}+{{\log }_{36}}98+{{3}^{{{\log }_{9}}\frac{1}{4}}}\).
进入组卷