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is there a proof for the perpendicular distance formula using vectors?

14-04-2010 11:48pm

#1

eoins23456

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Could anybody give me a link?

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Comments

#2 15-04-2010 5:51pm

zam

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Ah jaysis you need that for vectors? How exactly does that work?? :S

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#3 15-04-2010 6:41pm

MathsManiac

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This what you want?
http://mathworld.wolfram.com/Point-LineDistance2-Dimensional.html

Not sure if the LC examiners would like it.

What's wrong with the regular proof anyway?

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#4 16-04-2010 1:33am

Fringe

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The first part in that link is really weird and messy. It seems enough to just say that (a,b) is the normal vector to the line since we can take the normal vector of a 3d-plane, (a,b,c), and set c = 0 to constrain it to 2 dimensions. Then what follows is actually quite a nice elegant proof but it probably is a bit too unfamiliar for LC.

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