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Math Help - [Matricies] Finding Inverse?

  1. #1
    Junior Member Cthul's Avatar
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    [Matricies] Finding Inverse?


    I don't get it, someone explain?
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  2. #2
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    Quote Originally Posted by Cthul View Post

    I don't get it, someone explain?
    are you sure it's not hence find A^{-1}?
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  3. #3
    Junior Member Cthul's Avatar
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    I'm positive, I have to find the inverse of B somehow.
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  4. #4
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    Quote Originally Posted by Cthul View Post
    I'm positive, I have to find the inverse of B somehow.
    A is the inverse of B.
    and B is the inverse of A.
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  5. #5
    Junior Member Cthul's Avatar
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    Quote Originally Posted by BabyMilo View Post
    A is the inverse of B.
    and B is the inverse of A.
    I don't understand though, it asks me to multiply first and then find the inverse of B.
    A isn't a variable is it? [Edit]
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  6. #6
    MHF Contributor undefined's Avatar
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    Quote Originally Posted by Cthul View Post
    I don't understand though, it asks me to multiply first and then find the inverse of B.
    A isn't a variable is it? [Edit]
    Without performing the multiplication myself, but just based on context (the question plus other posts above me), I'm guessing you'll get the identity matrix.

    Quote Originally Posted by Cthul View Post
    A isn't a variable is it? [Edit]
    A is a variable, and it is a matrix. Variables can refer to lots of different mathematical objects, not just real numbers, etc.
    Last edited by undefined; April 21st 2010 at 02:25 AM. Reason: clarification
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  7. #7
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    Quote Originally Posted by Cthul View Post
    I don't understand though, it asks me to multiply first and then find the inverse of B.
    A isn't a variable is it? [Edit]
    when u time them together.
    you should get
    \begin{bmatrix}<br />
10 & 0 & 0\\ <br />
0 & 10 & 0\\ <br />
0 & 0 & 10<br />
\end{bmatrix}

    you should know  AA^{-1} = \frac{1}{DET} * Identity

    do u understand now?
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  8. #8
    Junior Member Cthul's Avatar
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    Quote Originally Posted by BabyMilo View Post
    when u time them together.
    you should get
    \begin{bmatrix}<br />
10 & 0 & 0\\ <br />
0 & 10 & 0\\ <br />
0 & 0 & 10<br />
\end{bmatrix}

    you should know  AA^{-1} = \frac{1}{DET} * Identity

    do u understand now?
    So it's
    AB=10I
    A=10IB^{-1}
    1/10*A=B^{-1}
    Right?
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  9. #9
    MHF Contributor undefined's Avatar
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    Quote Originally Posted by Cthul View Post
    So it's
    AB=10I
    A=10IB^{-1}
    1/10*A=B^{-1}
    Right?
    Looks good to me. I also confirmed the result with Mathematica.
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