Two vector $A$ and $B$ have equal magnitudes. Then the vector $\mathop A\limits^ \to + \mathop B\limits^ \to $ is perpendicular to
Two vector $A$ and $B$ have equal magnitudes. Then the vector $\mathop A\limits^ \to + \mathop B\limits^ \to $ is perpendicular to
$\mathop A\limits^ \to \times \mathop B\limits^ \to $
$\mathop A\limits^ \to - \mathop B\limits^ \to $
$3\mathop A\limits^ \to \times 3\mathop B\limits^ \to $
All of these
Two vector $A$ and $B$ have equal magnitudes. Then the vector $\mathop A\limits^ \to + \mathop B\limits^ \to $ is perpendicular to
$\vec A \times \vec B$ is a vector perpendicular to plane $\vec A + \vec B$ and hence perpendicular to $\vec A + \vec B$.