# [Dot Product] Vector Proection

by Highway
Tags: product, proection, vector
 HW Helper P: 6,189 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 $\vec a \cdot \vec w = 0$?
 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 $\vec a \cdot \vec w = 0$?