CET Karnataka Engineering CET - Karnataka Engineering Solved Paper-2004

  • question_answer
    The value of \[\left| \begin{matrix}    441 & 442 & 443  \\    445 & 446 & 447  \\    449 & 450 & 451  \\ \end{matrix} \right|\] is :

    A)  \[441\times 446\times 4510\]   

    B)  0

    C)                  -1                                          

    D)                  1

    Correct Answer: B

    Solution :

    We have, \[\left| \begin{matrix}    441 & 442 & 443  \\    445 & 446 & 447  \\    449 & 450 & 451  \\ \end{matrix} \right|\] On expanding we get,                 \[=441\left[ \left( 201146-201150 \right) \right]-442\] \[\left[ 200695-200703 \right]+443\left[ 200250-200254 \right]\] \[=-1764+3536-1772\] \[=3536-3536=0\] Alternate                 \[\left| \begin{matrix}    441 & 442 & 443  \\    445 & 446 & 447  \\    449 & 450 & 451  \\ \end{matrix} \right|\] \[=\left| \begin{matrix}    441 & 1 & 1  \\    445 & 1 & 1  \\    449 & 1 & 1  \\ \end{matrix} \right|\begin{matrix}    {{C}_{2}}\to {{C}_{2}}-{{C}_{1}}  \\    {{C}_{3}}\to {{C}_{3}}-{{C}_{2}}  \\ \end{matrix}\]= 0 (\[\because \] two columns are in dentical)


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