CUET Preparation Today
If $\vec a$ and $\vec b$are unit vectors and θ is the angle between them, then $|\frac{\vec a-\vec b}{2}|$ is: |
$\sin\frac{θ}{2}$ $\sin θ$ $2\sin θ$ $\sin 2θ$ |
$\sin\frac{θ}{2}$ |
$|\frac{\vec a-\vec b}{2}|^2=\frac{1}{4}(|\vec a|^2+|\vec b|^2-2\vec a.\vec b)=\frac{1}{4}(1+1-2\cos θ)=sin^2\frac{θ}{2}⇒|\frac{\vec a-\vec b}{2}|=sin\frac{θ}{2}$ |
