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Math Help - Matrices question

  1. #1
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    Matrices question

    Can somebody plz try to solve the matrices sum in the attached figure??
    Attached Thumbnails Attached Thumbnails Matrices question-2i2arkp.jpg  
    Last edited by mr fantastic; February 5th 2010 at 02:50 AM. Reason: Changed post title
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  2. #2
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    Quote Originally Posted by snigdha View Post
    Can somebody plz try to solve the matrices sum in the attached figure??

    This is not sum of matrices but product of matrices. Read carefully the definition of product of matrices.

    Tonio
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    Quote Originally Posted by tonio View Post
    This is not sum of matrices but product of matrices. Read carefully the definition of product of matrices.

    Tonio
    well tonio...u misunderstood me...by "sum" i mean to say "problem"... & not that sum which means addition..!!
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    Quote Originally Posted by snigdha View Post
    well tonio...u misunderstood me...by "sum" i mean to say "problem"... & not that sum which means addition..!!

    Well, is that a weird use of the word sum...!

    Tonio
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  5. #5
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    After multiplying this, we get,

    \begin{pmatrix}<br />
x^2+y^2 &0\\<br />
0 & -x^2-y^2<br />
\end{pmatrix}<br />
=<br />
\begin{pmatrix}<br />
1 &0\\<br />
0 & -1\\<br />
\end{pmatrix}

    Then, we have,

    x^2+y^2=1

    and all possible pairs are,

    (x,y)=(1,0), (0,1), (-1,0),(0,-1)
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  6. #6
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    Quote Originally Posted by tonio View Post
    Well, is that a weird use of the word sum...!

    Tonio
    Apparently our British friends often use "sum" to mean any kind of mathematics problem.

    Doing mathematics problems is "doing sums". If only it were that easy!
    Last edited by HallsofIvy; February 6th 2010 at 06:14 AM.
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  7. #7
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    Quote Originally Posted by kjchauhan View Post
    After multiplying this, we get,

    \begin{pmatrix}<br />
x^2+y^2 &0\\<br />
0 & -x^2-y^2<br />
\end{pmatrix}<br />
=<br />
\begin{pmatrix}<br />
1 &0\\<br />
0 & -1\\<br />
\end{pmatrix}

    Then, we have,

    x^2+y^2=1

    and all possible pairs are,

    (x,y)=(1,0), (0,1), (-1,0),(0,-1)
    Assuming that x and y are integers, yes. But that was not given in the problem. For x and y real, x can be any number such that -1\le x\le 1 and y= \pm\sqrt{1- x^2}
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  8. #8
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    Quote Originally Posted by HallsofIvy View Post
    Apparently our British friends often use "sum" to mean any kind of mathematics problem.
    Even we, the Indians do the same..!!
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  9. #9
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    Quote Originally Posted by HallsofIvy View Post
    Assuming that x and y are integers, yes. But that was not given in the problem. For x and y real, x can be any number such that -1\le x\le 1 and y= \pm\sqrt{1- x^2}
    Thats true.. Thanks.
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  10. #10
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    Quote Originally Posted by snigdha View Post
    Even we, the Indians do the same..!!
    Yes. Unfortunately, the "Raj" taught you a perverted form of the language!
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