## Algebra and Trigonometry 10th Edition

$u$ and $v$ are not orthogonal.
$u$ and $v$ are orthogonal vectors if and only if $u·v=0$ $u·v=⟨\frac{1}{4},-\frac{1}{2}⟩⋅⟨-2,4⟩=\frac{1}{4}(-2)+(-\frac{1}{2})(4)=-\frac{2}{4}-2=-\frac{1}{2}-\frac{4}{2}=-\frac{5}{2}$