Mathematics 9709 · AS & A Level · Vectors

Vectors — practice question

The line $l$ is described by $\mathbf{r} = \mathbf{i} - 2\mathbf{j} - 3\mathbf{k} + \lambda(-\mathbf{i} + \mathbf{j} + 2\mathbf{k})$. The points $A$ and $B$ are given by the position vectors $-2\mathbf{i} + 2\mathbf{j} - \mathbf{k}$ and $3\mathbf{i} - \mathbf{j} + \mathbf{k}$ respectively.
(a)[2]

Determine a unit vector in the direction of $l$.

(b)[2]

The line $m$ goes through the points $A$ and $B$. Find a vector equation for $m$.

(c)[5]

Decide whether lines $l$ and $m$ are parallel, intersecting or skew.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Calculate the modulus of the vector.

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