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[parent] Viewing Message
``Re: Proof of the Lagrange Identity?'' by alozano on 2006-11-12 12:22:36
The factor of 2 is definitely correct:

(x1y1+x2y2)^2 = (x1y1)^2 + (x2y2)^2 + 2*x1y1x2y2

= (x1y1)^2 + (x2y2)^2 + 2*x1y2x2y1

Alvaro
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