Let $\theta$ be the angle between the unit vectors $a$ and $b$, where \(0

Question

Let $\theta$ be the angle between the unit vectors $a$ and $b$, where $0 < \theta < \pi$. Express $\vert{}\mathbf{a} - \mathbf{b}\vert{}$ in terms of $\sin \frac{1}{2}\theta$

Accepted Answer

$2\sin\frac{\theta}{2}$