# How do you find the projection of u onto v given u=<4, 2> and v=<1, -2>?

$\vec{u}$ and $\vec{v}$ are perpendicular
The projection of $\vec{u}$ onto $\vec{v}$ is given by
(vecu.vecv)/(∥vecv∥*∥vecv∥)vecv
The dot product vecu.vecv=〈4,2〉.〈1,-2〉=4-4=0
Therefore $\vec{u}$ and $\vec{v}$ are perpendicular since the dot product $= 0$
$\therefore$ no projection is possible