# [Dot Product] Vector Proection

by Highway
Tags: product, proection, vector
 P: 349 1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution I am not sure what to do here -- I know that the projection of u onto a "dotted" with w = 0 by definition, but I don't know how to show this. added this second part after plugging in for the definition of the projection we derived in class, then simplified. . .
 P: 349 anyone?
 HW Helper P: 6,188 Hi Highway! You have an expression for the projection. Can you substitute that (and only that) in the formula you have for w? To show that 2 vectors are orthogonal, you need to show that their dot product is zero. That is, that $\vec a \cdot \vec w = 0$. What you need to know, is that there are calculation rules for dot products. For instance $\vec a \cdot (\vec b+\vec c) = \vec a \cdot \vec b + \vec a \cdot \vec c$. Can you simplify the expression for $\vec a \cdot \vec w = 0$?
P: 349
[Dot Product] Vector Proection

 Quote by I like Serena Hi Highway! You have an expression for the projection. Can you substitute that (and only that) in the formula you have for w? To show that 2 vectors are orthogonal, you need to show that their dot product is zero. That is, that $\vec a \cdot \vec w = 0$. What you need to know, is that there are calculation rules for dot products. For instance $\vec a \cdot (\vec b+\vec c) = \vec a \cdot \vec b + \vec a \cdot \vec c$. Can you simplify the expression for $\vec a \cdot \vec w = 0$?
Thanks!! I got it figured out :P

 HW Helper P: 6,188 Congrats!

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