Practicing Success
Practicing Success
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Let $\vec a$ be a unit vector perpendicular to unit vectors $\vec b$ and $\vec c$ and if the angle between $\vec b$ and $\vec c$ is $α$, then $\vec b×\vec c$ is |
$±(\cos α)\vec a$ $±(cosec α)\vec a$ $±(\sin α)\vec a$ none of these |
$±(\sin α)\vec a$ |
We have, $\vec a=±\frac{\vec b×\vec c}{|\vec b×\vec c|}$ $⇒\vec b×\vec c=±|\vec b×\vec c|\vec a=±(\sin α)\vec a$ $[∵|\vec b×\vec c|=\sin α]$ |
