KVPY Sample Paper KVPY Stream-SX Model Paper-31

  • question_answer
    Find the value of c for which the following equations have non trivial solutions:
    \[cx-y-z=0\]
    \[-cx+y-cz=0\]
    \[x+y-cz=0\]

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

    B) \[-1\]

    C) \[2\]     

    D) \[0\]

    Correct Answer: B

    Solution :

    \[\left| \begin{matrix}    C & -1 & -1  \\    -C & 1 & -C  \\    1 & 1 & -C  \\ \end{matrix} \right|=0\]\[\Rightarrow \]\[\left| \begin{matrix}    0 & 0 & -(1+C)  \\    -C & 1 & -C  \\    1 & 1 & -C  \\ \end{matrix} \right|=0\]\[\Rightarrow \]\[-(1+C)(-C-1)=0\]\[\Rightarrow \]\[C=-1.\]


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