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    Proving the equality of two expressions





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    Re: Proving the equality of two expressions

    What is your argument to prove RHS to LHS?
    I don't have emotions and sometimes that makes me very sad.

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    Re: Proving the equality of two expressions

    It's a pretty long-winded algebraic exercise, basically I just just subbed in the expression for b = (X'X)^{-1}X'y, then expanded out the transposes, after a lot of algebra I can get the LHS. Ofcourse I tried to backtrack from this and see if I could go from the LHS to the RHS, but there would be no way I could have thought of those algebraic manipulations if I were not given the RHS already haha

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    Re: Proving the equality of two expressions

    Quote Originally Posted by TrueTears View Post
    but there would be no way I could have thought of those algebraic manipulations if I were not given the RHS already haha
    If you're doing a proof then why does it matter? Are you just interested if there is a more clear way to to it?
    I don't have emotions and sometimes that makes me very sad.

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    Re: Proving the equality of two expressions

    Well initially I wasn't given the RHS, but after I saw the solutions, I backtracked from the answer (which is the RHS), to the LHS (which is what I had initially), so yes I am wondering if there is a clearer method (in the sense that doesn't require me to backtrack from the answer itself).

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    Re: Proving the equality of two expressions

    What exactly was the question asking you to do then?
    I don't have emotions and sometimes that makes me very sad.

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    Re: Proving the equality of two expressions

    It's part of a big overall problem, kinda hard to put it into context, but essentially I had to strictly go from the LHS to the RHS without knowing the expression of the RHS first.

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    Re: Proving the equality of two expressions

    Well without you even describing what the problem actually was I don't see how I can help you with any intuition for how to get there...
    I don't have emotions and sometimes that makes me very sad.

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    Re: Proving the equality of two expressions


    Ok, I'll type it up now, please check this post soon.

    Thanks for your help Dason.

    -----------------------------------------------------------------------------
    Ok here it is:



    My working out to derive p(β|σ,y) is:




    The line marked with a blue dot is where I was stuck, only after I was told that the next step was the line marked in a red dot, then I knew what to do. As you can see, without knowing the step marked by the red dot, I couldn't have continued. So how can I get from the blue dot to the red dot without knowing the expression in the red dot
    Last edited by TrueTears; 08-27-2013 at 11:33 AM.

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