(a)[2]
Determine a vector equation for the line through $A$ and $B$.
(b)[4]
Using a scalar product, determine the exact value of $\cos BAC$.
(c)[3]
Hence determine the exact area of triangle $ABC$.
Mathematics 9709 · AS & A Level · Vectors
Vectors — practice question
Relative to origin O, the position vectors of points A, B and C are given by $\overrightarrow{OA} = \begin{pmatrix} 1 \\ -4 \\ 2 \end{pmatrix}$, $\overrightarrow{OB} = \begin{pmatrix} -2 \\ 1 \\ 3 \end{pmatrix}$ and $\overrightarrow{OC} = \begin{pmatrix} 2 \\ 3 \\ 5 \end{pmatrix}$.
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