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
    \[\left| \,\begin{matrix}    1/a & {{a}^{2}} & bc  \\    1/b & {{b}^{2}} & ca  \\    1/c & {{c}^{2}} & ab  \\ \end{matrix}\, \right|=\] [RPET 1990, 99]

    A) \[abc\]

    B) \[1/abc\]

    C) \[ab+bc+ca\]

    D) 0

    Correct Answer: D

    Solution :

    \[\left| \,\begin{matrix}    1/a & {{a}^{2}} & bc  \\    1/b & {{b}^{2}} & ca  \\    1/c & {{c}^{2}} & ab  \\ \end{matrix}\, \right|\]\[=\frac{1}{abc}\,\left| \,\begin{matrix}    1 & {{a}^{3}} & abc  \\    1 & {{b}^{3}} & abc  \\    1 & {{c}^{3}} & abc  \\ \end{matrix}\, \right|=\frac{abc}{abc}\left| \,\begin{matrix}    1 & {{a}^{3}} & 1  \\    1 & {{b}^{3}} & 1  \\    1 & {{c}^{3}} & 1  \\ \end{matrix}\, \right|=0\]


You need to login to perform this action.
You will be redirected in 3 sec spinner