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

Toán Lớp 10: Viết pt đg rron (C) nhận AB là đg Kính Biết a) A(1;1) B(9,2) b) A(3,5) B(9,2) Cần trợ giúp ạ 5sao Ạ cmon C) A(-3,4) B(1,-1)

Toán Lớp 10: Viết pt đg rron (C) nhận AB là đg Kính Biết
a) A(1;1) B(9,2)
b) A(3,5) B(9,2)
Cần trợ giúp ạ
5sao
Ạ cmon
C) A(-3,4) B(1,-1)

Comments ( 1 )

  1.  Gọi $I$ là trung điểm $AB$ cho tất cả câu a,b,c
    a)
    $\begin{array}{l} \left\{ \begin{array}{l} {x_I} = \dfrac{{{x_A} + {x_B}}}{2} = \dfrac{{1 + 9}}{2} = 5\\ {y_I} = \dfrac{{{y_A} + {y_B}}}{2} = \dfrac{{1 + 2}}{2} = \dfrac{3}{2} \end{array} \right.\\  \Rightarrow I\left( {5;\dfrac{3}{2}} \right)\\ R = \dfrac{{AB}}{2} = \dfrac{{\sqrt {{{\left( {9 – 1} \right)}^2} + {{\left( {2 – 1} \right)}^2}} }}{2} = \dfrac{{\sqrt {65} }}{2}\\ \left( C \right):{\left( {x – 5} \right)^2} + {\left( {y – \dfrac{3}{2}} \right)^2} = \dfrac{{65}}{4} \end{array}$
    b)
    $\begin{array}{l}
    \left\{ \begin{array}{l}
    {x_I} = \dfrac{{{x_A} + {x_B}}}{2} = \dfrac{{3 + 9}}{2} = 6\\
    {y_I} = \dfrac{{{y_A} + {y_B}}}{2} = \dfrac{{5 + 2}}{2} = \dfrac{7}{2}
    \end{array} \right.\\
     \Rightarrow I\left( {6;\dfrac{7}{2}} \right)\\
    R = \dfrac{{AB}}{2} = \dfrac{{\sqrt {{{\left( {9 – 3} \right)}^2} + {{\left( {5 – 2} \right)}^2}} }}{2} = \dfrac{{3\sqrt 5 }}{2}\\
    \left( C \right):{\left( {x – 6} \right)^2} + {\left( {y – \dfrac{7}{2}} \right)^2} = \dfrac{{45}}{4}
    \end{array}$
    c)
    $\begin{array}{l}
    \left\{ \begin{array}{l}
    {x_I} = \dfrac{{{x_A} + {x_B}}}{2} = \dfrac{{1 – 3}}{2} =  – 1\\
    {y_I} = \dfrac{{{y_A} + {y_B}}}{2} = \dfrac{{4 – 1}}{2} = \dfrac{3}{2}
    \end{array} \right.\\
     \Rightarrow I\left( { – 1;\dfrac{3}{2}} \right)\\
    R = \dfrac{{AB}}{2} = \dfrac{{\sqrt {{{\left( {1 + 3} \right)}^2} + {{\left( {4 + 1} \right)}^2}} }}{2} = \dfrac{{\sqrt {41} }}{2}\\
    \left( C \right):{\left( {x + 1} \right)^2} + {\left( {y – \dfrac{3}{2}} \right)^2} = \dfrac{{41}}{4}
    \end{array}$
     

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

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