Vectors I: scalar and vector products

Question code: bbb7A2CG746C32

Question 1103

Referred to the origin O,{O,} the position vectors of the points A{A} and B{B} are
7ij+2k and 3i7j+7k7 \mathbf{i} - \mathbf{j} + 2 \mathbf{k} \quad \textrm{ and } \quad - 3 \mathbf{i} - 7 \mathbf{j} + 7 \mathbf{k}
respectively.

(i)

Show that OA{OA} and that OB{OB} are perpendicular.
[2]

(ii)

Find the position vector of the point V{V} on AB{AB} extended such that AB:AV=3:5.{AB:AV = 3:5.}
[3]

(iii)

The point C{C} has position vector 4i+6j3k.{4 \mathbf{i} + 6 \mathbf{j} - 3 \mathbf{k}.} Use a vector product to find the exact area of triangle OBC{OBC}
[4]
Answer

(ii)

13(29i33j+31k){\frac{1}{3} ( - 29 \mathbf{i} - 33 \mathbf{j} + 31 \mathbf{k} )}

(iii)

12902{\frac{1}{2} \sqrt{902}}
Question code: bbb7A2CG746C32