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
    \[\left| \,\begin{matrix}    1 & 1+ac & 1+bc  \\    1 & 1+ad & 1+bd  \\    1 & 1+ae & 1+be  \\ \end{matrix}\, \right|=\] [MP PET 1996]

    A) 1

    B) 0

    C) 3

    D) \[a+b+c\]

    Correct Answer: B

    Solution :

    Applying \[{{C}_{3}}\to {{C}_{3}}-{{C}_{1}}\]and \[{{C}_{2}}\to {{C}_{2}}-{{C}_{1}}\], we get \[\left| \,\begin{matrix}    1 & ac & bc  \\    1 & ad & bd  \\    1 & ae & be  \\ \end{matrix}\, \right|=ab\left| \,\begin{matrix}    1 & c & c  \\    1 & d & d  \\    1 & e & e  \\ \end{matrix}\, \right|=0\], \[\{\because {{C}_{2}}\equiv {{C}_{3}}\}\].


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