If in a triangle,

MATHEMATICS · Single correct · A Level · Mathematics · Vectors · Vectors

Problem

If in a triangle,

\mathbf{AB} = \mathbf{a}

\mathbf{AC} = \mathbf{b}

and D, E are the mid-points of AB and AC respectively, then

\mathbf{DE}

is equal to (1)

\frac{\mathbf{a}}{4} - \frac{\mathbf{b}}{4}

(2)

\frac{\mathbf{a}}{2} - \frac{\mathbf{b}}{2}

(3)

\frac{\mathbf{b}}{4} - \frac{\mathbf{a}}{4}

(4)

\frac{\mathbf{b}}{2} - \frac{\mathbf{a}}{2}