2010-II-39

21-06-2023 app.cch 尚無留言

答案：C

\begin{array}{rcl} \frac{1}{\sqrt{a^{3}}} \div \frac{\sqrt{b}}{a} & = & \frac{1}{\sqrt{a^{3}}} \times \frac{a}{\sqrt{b}} \\ = & a^{\frac{- 3}{2}} \times a b^{\frac{- 1}{2}} \\ = & a^{\frac{- 3}{2} + 1} \times b^{\frac{- 1}{2}} \\ = & a^{\frac{- 1}{2}} b^{\frac{- 1}{2}} \\ = & (a b)^{\frac{- 1}{2}} \\ = & \frac{1}{\sqrt{a b}} \\ = & \frac{1}{\sqrt{a b}} \times \frac{\sqrt{a b}}{\sqrt{a b}} \\ = & \frac{\sqrt{a b}}{a b} \end{array}

2010, 卷二, 香港中學會考指數定律

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