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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 12: Câu 3: Cho `y=\sqrt{3x -x²}+m`. Tìm `m` để `max_{[0;\sqrt{3}]} y=3\sqrt{2}`

Toán Lớp 12: Câu 3: Cho y=\sqrt{3x -x²}+m. Tìm m để max_{[0;\sqrt{3}]} y=3\sqrt{2}

Comments ( 1 )

  1. Giải đáp:
    $m=\dfrac{-3+6\sqrt{2}}{2}.$
    Lời giải và giải thích chi tiết:
    $y=\sqrt{3x-x^2}+m \ \ \ \ D=[0;3]\\ y’=\dfrac{3-2x}{2\sqrt{3x-x^2}}\\ y’=0 \Leftrightarrow x=\dfrac{3}{2}$
    BBT:
    \begin{array}{|c|ccccccccc|} \hline x&0&&\dfrac{3}{2}&&\sqrt{3}\\\hline y’&&+&0&-&\\\hline &&&y\left(\dfrac{3}{2}\right)\\y&&\nearrow&&\searrow&\\&y(0)&&&&y(\sqrt{3})\\\hline\end{array}
    Dựa vào  BBT $\Rightarrow \underset{\left[0;\sqrt{3}\right]}{max}y=y\left(\dfrac{3}{2}\right)$
    $\Leftrightarrow 3\sqrt{2}=\dfrac{3}{2}+m\\ \Leftrightarrow m= 3\sqrt{2}-\dfrac{3}{2}\\ \Leftrightarrow m=\dfrac{-3+6\sqrt{2}}{2}.$

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222-9+11+12:2*14+14 = ? ( )