The position vectors of four points and are and respectively

MATHEMATICS · Subjective · A Level · Mathematics · Vectors · Vectors

Problem

The position vectors of four points

P, Q, R

and

S

are

2 \boldsymbol{a} + 4 \boldsymbol{c}, 5 \boldsymbol{a} + 3 \boldsymbol{b} + 4 \boldsymbol{c}, -2 \boldsymbol{b} + \boldsymbol{c}

and

2 \boldsymbol{a} + \boldsymbol{c}

respectively. Prove that

PQ

is parallel to

RS