Comments on: About http://danboykis.com Thinking somewhat carefully Wed, 18 Jan 2012 18:48:19 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: Eugene http://danboykis.com/about/comment-page-1/#comment-330 Eugene Mon, 17 Oct 2011 11:00:44 +0000 http://danboykis.com/?page_id=17#comment-330 I was looking through your derivation of sums of squares and found some things that I don't yet understand. I'd like your help in understanding some of it... Please refer to this website http://danboykis.com/2009/03/derivation-for-sum-of-squares/ Starting just after where it says "Here's the derivation:" I can follow the first line of symbols. I can also understand how you get from the first step in the 2nd line to the next step in the 2nd line. However I don't understand how you go from the second step to the 3rd step in the second line. Is this an identity of some sort? Or is this "common knowledge" when doing "sigma math"? Please help! I was looking through your derivation of sums of squares and found some things that I don’t yet understand. I’d like your help in understanding some of it…

Please refer to this website http://danboykis.com/2009/03/derivation-for-sum-of-squares/ Starting just after where it says “Here’s the derivation:” I can follow the first line of symbols. I can also understand how you get from the first step in the 2nd line to the next step in the 2nd line. However I don’t understand how you go from the second step to the 3rd step in the second line. Is this an identity of some sort? Or is this “common knowledge” when doing “sigma math”?

Please help!

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