Manipal Engineering Manipal Engineering Solved Paper-2010

  • question_answer
    If\[A\]is an orthogonal matrix, then

    A) \[\det \,\,A=not\,\,exist\]          

    B) \[\det \,\,A=0\]

    C) \[\det \,\,A=\pm 1\]     

    D)         None of these

    Correct Answer: C

    Solution :

    Since,\[A\]is an orthogonal matrix, therefore, \[AA=I\Rightarrow |A\cdot A|=|I|\Rightarrow |A|\cdot |A|=1\] \[\Rightarrow \]               \[|A|\cdot |A|=1\]                        \[(\because |I|\,\,=1)\] \[\Rightarrow \]               \[|A{{|}^{2}}=1\]                                             \[(\because \,\,|A|=|A|)\] \[\Rightarrow \]               \[|A|=\pm 1\]


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