Question 1207

Vectors I: Basics, Dot and Cross Products
2007 Paper 1 Question 6 Variant

Question

Referred to the origin O,{O,} the position vectors of the points A{A} and B{B} are
3i5j+3k and i+3j+pk\begin{align*} && 3 \mathbf{i} - 5 \mathbf{j} + 3 \mathbf{k} \\ \textrm{ and } \quad && \mathbf{i} + 3 \mathbf{j} + p \mathbf{k} \end{align*}
respectively.
(i)
Find the value of p.{p.}
[2]
(ii)
Find the position vector of the point M{M} on the line segment AB{AB} such that AM:MB=2:3.{AM:MB = 2:3.}
[3]
(iii)
The point C{C} has position vector 5ij4k.{5 \mathbf{i} - \mathbf{j} - 4 \mathbf{k}.} Use a vector product to find the exact area of triangle OAC.{OAC.}
[4]

Answer