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Math Help - Inverse Matrix

  1. #1
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    Inverse Matrix

    Need to know the inverse for the matrix (plz teach me the method also not the answer)

    -5 -2 -2
    2 1 0
    1 0 1



    it is 3x3 matrix
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  2. #2
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    Quote Originally Posted by someone21 View Post
    Need to know the inverse for the matrix (plz teach me the method also not the answer)

    -5 -2 -2
    2 1 0
    1 0 1



    it is 3x3 matrix
    Read this: tutOR: Matrix Inverse

    Why do you need to know? If it's for an assignment or test, you must already have been taught how to do it ....?
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  3. #3
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    Hello,

    The method in Mr F's link is obviously the best and maybe the simplest...

    Here the indigestible direct formula :

    If A=\begin{pmatrix} a&b&c \\ d&e&f \\ g&h&i \end{pmatrix}

    A^{-1}=\frac{1}{\text{det} A} \begin{pmatrix} ei-fh&ch-bi&bf-ce \\ fg-di&ai-cg&cd-af \\ dh-eg&bg-ah&ae-bd \end{pmatrix}
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  4. #4
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    What do you mean indigest and most importantly, is there any quicker way to find the inverse of the matrix or gauss jordan elimination

    So any quicker ways to find the solutions for matrix
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  5. #5
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    Quote Originally Posted by someone21 View Post
    What do you mean indigest and most importantly, is there any quicker way to find the inverse of the matrix or gauss jordan elimination

    So any quicker ways to find the solutions for matrix
    Yes: Use technology.

    Otherwise, read post #2.
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  6. #6
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    Quote Originally Posted by Moo View Post
    Hello,

    The method in Mr F's link is obviously the best and maybe the simplest...

    Here the indigestible direct formula :

    If A=\begin{pmatrix} a&b&c \\ d&e&f \\ g&h&i \end{pmatrix}

    A^{-1}=\frac{1}{\text{det} A} \begin{pmatrix} ei-fh&ch-bi&bf-ce \\ fg-di&ai-cg&cd-af \\ dh-eg&bg-ah&ae-bd \end{pmatrix}
    Had to bring it again

    Will that indigestible method work in all 3x3 matrix
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  7. #7
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    Quote Originally Posted by someone21 View Post
    Had to bring it again

    Will that indigestible method work in all 3x3 matrix
    Is matrix A in moo's post a 3x3 matrix? Did moo state any exceptions to the method?
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  8. #8
    Moo
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    Quote Originally Posted by mr fantastic View Post
    Is matrix A in moo's post a 3x3 matrix? Did moo state any exceptions to the method?
    No I didn't state any, but if the matrix is not invertible, that is to say if det ~ A=0, then we can talk about an exception
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  9. #9
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    Quote Originally Posted by Moo View Post
    No I didn't state any, but if the matrix is not invertible, that is to say if det ~ A=0, then we can talk about an exception

    Lol, sorry but what is !!!!det A!!! not yet learned

    and how to know that the inverse in not possible, i mean you might think there may be an answer to the matrix and continue solving it with various numbers, So any better ways
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  10. #10
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    Quote Originally Posted by someone21 View Post
    Lol, sorry but what is !!!!det A!!! not yet learned

    and how to know that the inverse in not possible, i mean you might think there may be an answer to the matrix and continue solving it with various numbers, So any better ways
    When you learn about the determinant you will get a method for testing whether the inverse of a given matrix exists. I have already given the general apporach for finding the inverse of a matrix. You can use moo's for a 3x3, if the order is higher you're stuck with with what I've already told you.

    It sounds like it might be better if you wait until you've been taught more regarding this subject.
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