JEE Main & Advanced JEE Main Paper (Held on 7 May 2012)

  • question_answer
    If\[A=\left( \begin{matrix}    \alpha -1  \\    0  \\    0  \\ \end{matrix} \right),B=\left( \begin{matrix}    \alpha +1  \\    0  \\    0  \\ \end{matrix} \right)\]be two matrices, then \[A{{B}^{T}}\]is a non-zero matrix for |a| not equal to   JEE Main Online Paper (Held On 07 May 2012)

    A) 2                                             

    B)                        0

    C)                        1     

    D)                        3

    Correct Answer: C

    Solution :

                    Let\[A=\left( \begin{matrix}    \alpha -1  \\    0  \\    0  \\ \end{matrix} \right),B=\left( \begin{matrix}    \alpha +1  \\    0  \\    0  \\ \end{matrix} \right)\]be two matrices. \[A{{B}^{T}}=\left( \begin{matrix}    \alpha -1  \\    0  \\    0  \\ \end{matrix} \right),(\alpha +1\,\,0\,\,\,0)\]\[\left( \begin{matrix}    {{\alpha }^{2}}-1  \\    0  \\    0  \\ \end{matrix}\,\,\,\,\,\,\,\,\begin{matrix}    0 & 0  \\    0 & 0  \\    0 & 0  \\ \end{matrix} \right)\] Thus, \[A{{B}^{T}}\]is non-zero matrix for\[|\alpha |\ne 1\]


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