Question

tim x de bieu thuc sau co nghia

\(\dfrac{1}{\sqrt{2x-x^2}}\)

Answer 1

Giải:

Để biểu thức có nghĩa thì:

\(2x-x^2>0\)

\(\Leftrightarrow x\left(2-x\right)>0\)

\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x>0\\2-x>0\end{matrix}\right.\\\left\{{}\begin{matrix}x< 0\\2-x< 0\end{matrix}\right.\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x>0\\x< 2\end{matrix}\right.\\\left\{{}\begin{matrix}x< 0\\x>2\end{matrix}\right.\end{matrix}\right.\Leftrightarrow0< x< 2\)

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