JEE Main & Advanced Mathematics Determinants & Matrices Question Bank System of linear equations, Some special determinants, differentiation and integration of determinants

  • question_answer
    For what value of \[\lambda \], the system of equations \[x+y+z=6,x+2y+3z=10,\]\[x+2y+\lambda z=12\]is inconsistent [AIEEE 2002]

    A) \[\lambda =1\]

    B) \[\lambda =2\]

    C) \[\lambda =-2\]

    D) \[\lambda =3\]

    Correct Answer: D

    Solution :

    Given system will be inconsistent when \[D=0\] \[\left| \,\begin{matrix}    1 & 1 & 1  \\    1 & 2 & 3  \\    1 & 2 & \lambda   \\ \end{matrix}\, \right|\,=0\] Applying \[{{C}_{1}}\to {{C}_{1}}-{{C}_{2}}\] and \[{{C}_{2}}\to {{C}_{2}}-{{C}_{3}}\] Þ \[\left| \,\begin{matrix}    0 & 0 & 1  \\    -1 & -1 & 3  \\    -1 & 2-\lambda  & \lambda   \\ \end{matrix}\, \right|\,=0\]Þ \[-1(2-\lambda )-1=0\Rightarrow \lambda =3\].


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