The points PPP, QQQ, R R\,R and S S\,S have position vectors p=2i+j+4k\mathbf{p} = 2\mathbf{i} + \mathbf{j} + 4\mathbf{k}p=2i+j+4k, q=5i−j+10k\mathbf{q} = 5\mathbf{i} - \mathbf{j} + 10\mathbf{k}q=5i−j+10k, r=−i+4j−2k\mathbf{r} = -\mathbf{i} + 4\mathbf{j} - 2\mathbf{k}r=−i+4j−2k and s=5i+0j+10k\mathbf{s} = 5\mathbf{i} + 0\mathbf{j} + 10\mathbf{k}s=5i+0j+10k
Show that PQ⃗\vec{PQ}PQ is parallel to RS⃗\vec{RS}RS
