로그 계산

$a$$\displaystyle = 2 \log {\frac{1}{\sqrt{10}}} + \log _{2} 20$ $\displaystyle = 2 \log \left( \frac{1}{10} \right) ^{\frac{1}{2}} + \log _{2} \left( 2 \times 10 \right)$ $= \log 10 ^{-1} + 1 + \log _{2} 10$ $= \log _{2} 10$ $\therefore$ $a \times b$$= \log _{2} 10 \times \log 2$$\displaystyle = \frac{\log 10}{\log 2} \times \log 2$ $= \log 10$$= 1$