Hi, I am having trouble with this proof, I am wondering what to do because the way I have attempted it is incorrect.(adsbygoogle = window.adsbygoogle || []).push({});

I want to prove

||x-y|| = ||x|| ||y|| ||x bar - y bar||

where

x and y are vectors in Rn

and u bar is defined by u/(||u||^2)

so the question asks to prove this analytically, I couldn't figure out how to do so, the only attempt I made was mathematically by expanding the right side using the formula for norm and trying to simplify it to the left. Anyway that results in a mess and I was wondering where to start.

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# Help with a proof.

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