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Math Help - DMAS rule in matrices

  1. #1
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    Question DMAS rule in matrices

    Will Addition and subtraction order as told by DMAS rule will be followed while solving matrices question ?

    i m asking because i have seen a question where if DMAS rule is followed regarding addition and subtraction then the answer is not correct.
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  2. #2
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    Re: DMAS rule in matrices

    Quote Originally Posted by haftakhan View Post
    Will Addition and subtraction order as told by DMAS rule will be followed while solving matrices question ?

    i m asking because i have seen a question where if DMAS rule is followed regarding addition and subtraction then the answer is not correct.
    Since division is not defined for matrices, the rule is not even valid.

    What was the question, what answer did you get?
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  3. #3
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    Re: DMAS rule in matrices

    Yes, multiplication of matrices precedes addition. To calculate AB+C, first multiply AB then add C. If you intend that B should be added to C first, the write A(B+ C). As mr fantastic said, there is no "division" defined for matrices. First, because many matrices do not have an inverse, second, because multiplication of matrices is not commutative so even if a matrix, A, has an inverse, we could have either A^{-1}B or BA^{-1} while "B/A" is ambiguous. With that proviso, precedence of operations is the same for matrices as for numbers: PEMAS where I have just dropped the "M".
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