JEE Main & Advanced Mathematics Determinants & Matrices Question Bank Expansion of determinants, Solution of equation in the form of determinants and properties of determinants

  • question_answer
    The value of the determinant \[\left| \,\begin{matrix}    1 & 1 & 1  \\    b+c & c+a & a+b  \\    b+c-a & c+a-b & a+b-c  \\ \end{matrix}\, \right|\] is [RPET 1986]

    A) abc

    B) \[a+b+c\]

    C) \[ab+bc+ca\]

    D) None of these

    Correct Answer: D

    Solution :

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


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