JEE Main & Advanced Mathematics Rectangular Cartesian Coordinates Question Bank Points related to triangle (Orthocente Circumcentre Incentre), Area of some geometrical figures Collinearity

  • question_answer
    The area of triangle formed by the points \[(a,b+c),\] \[(b,c+a),\] \[(c,\,a+b)\]  is equal to [Pb. CET 2003]

    A) \[abc\]

    B) \[{{a}^{2}}+{{b}^{2}}+{{c}^{2}}\]

    C) \[ab+bc+ca\]

    D) 0

    Correct Answer: D

    Solution :

    Area of triangle \[=\frac{1}{2}\left| \,\begin{matrix}    a & b+c & 1  \\    b & c+a & 1  \\    c & a+b & 1  \\ \end{matrix}\, \right|\]    \[=\frac{1}{2}\left| \,\begin{matrix}    a+b+c & b+c & 1  \\    b+c+a & c+a & 1  \\    c+a+b & a+b & 1  \\ \end{matrix}\, \right|\] \[=\frac{1}{2}(a+b+c)\,\left| \begin{matrix}    1 & b+c & 1  \\    1 & c+a & 1  \\    1 & a+b & 1  \\ \end{matrix} \right|=0\].


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