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

Toán Lớp 9: Tìm m để hàm số y=f(x)=(cănm^2+4 -m)x^2 -2mx+5 thỏa mãn điều kiện f(0)=f(1)

Toán Lớp 9: Tìm m để hàm số y=f(x)=(cănm^2+4 -m)x^2 -2mx+5 thỏa mãn điều kiện f(0)=f(1)

Comments ( 1 )

  1. ~rai~
    \(f(x)=(\sqrt{m^2+4}-m)x^2-2mx+5\\\text{Ta có:}\\+)f(0)=(\sqrt{m^2+4}-m).0^2-2m.0+5\\\quad\quad\quad=5.\\+)f(1)=(\sqrt{m^2+4}-m).1^2-2m.1+5\\\quad\quad\quad=\sqrt{m^2+4}-m-2m+5\\\quad\quad\quad=\sqrt{m^2+4}-3m+5\\f(0)=f(1)\\\Leftrightarrow \sqrt{m^2+4}-3m+5=5\\\Leftrightarrow \sqrt{m^2+4}=3m\quad(m\ge 0)\\\Leftrightarrow (\sqrt{m^2+4})^2=(3m)^2\\\Leftrightarrow m^2+4=9m^2\\\Leftrightarrow 8m^2=4\\\Leftrightarrow m^2=\dfrac{1}{2}\\\Leftrightarrow m=\dfrac{\sqrt{2}}{2}.\quad\text{(do }m\ge 0)\\\text{Vậy }m=\dfrac{\sqrt{2}}{2}.\)

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

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