Bài 2.90 trang 136 SBT giải tích 12

Tìm \(\displaystyle  x\), biết \(\displaystyle  {\left( {\sqrt 2 } \right)^x} = \sqrt[3]{2}\).

A. \(\displaystyle  x = 3\)                    B. \(\displaystyle  x = \frac{3}{2}\)

C. \(\displaystyle  x = \frac{2}{3}\)                  D. \(\displaystyle  x = \frac{1}{6}\)

Lời giải

\(\displaystyle  {\left( {\sqrt 2 } \right)^x} = \sqrt[3]{2}\)\(\displaystyle   \Leftrightarrow {2^{\frac{x}{2}}} = {2^{\frac{1}{3}}}\) \(\displaystyle   \Leftrightarrow \frac{x}{2} = \frac{1}{3} \Leftrightarrow x = \frac{2}{3}\).

Chọn C.


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