JEE Main & Advanced JEE Main Paper (Held on 08-4-2019 Morning)

  • question_answer
    The greatest value of \[c\in R\]for which the system of linear equations
    \[xcycz=0\]
    \[cxy+cz=0\]
    \[cx+cyz=0\]
    has a non-trivial solution, is :
    [JEE Main 8-4-2019 Morning]

    A) \[\frac{1}{2}\]

    B) -1

    C) 0                                 

    D) 2

    Correct Answer: A

    Solution :

    For non-trivial solution D = 0 \[\left| \begin{matrix}    1 & -c & -c  \\    c & -1 & c  \\    c & c & -1  \\ \end{matrix} \right|=0\Rightarrow 2{{c}^{3}}-3{{c}^{2}}-1=0\] \[\Rightarrow \]\[{{(c+1)}^{2}}(2c-1)=0\] \[\therefore \]Greatest value of c is \[\frac{1}{2}\]                  


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