Salam Academy
Paper 2 · Module

Further vectors

2 subtopics≈ 95 min in total
  1. Vector product and planes

    a×b\mathbf a\times\mathbf b is a vector perpendicular to both a\mathbf a and b\mathbf b, of length ∣a∣∣b∣sin⁡θ|\mathbf a||\mathbf b|\sin\theta. A plane is fixed by a point and a normal n\mathbf n: r⋅n=a⋅n\mathbf r\cdot\mathbf n=\mathbf a\cdot\mathbf n, or ax+by+cz=dax+by+cz=d. Substituting a line into a plane finds where they meet.

    ≈ 50 min
  2. Shortest distances and triple products

    The shortest distance is always along a perpendicular. From point PP to plane r⋅n=d\mathbf r\cdot\mathbf n=d: ∣p⋅n−d∣∣n∣\frac{|\mathbf p\cdot\mathbf n-d|}{|\mathbf n|}. Between skew lines: project the join of two points onto n=d1×d2\mathbf n=\mathbf d_1\times\mathbf d_2. The triple product a⋅(b×c)\mathbf a\cdot(\mathbf b\times\mathbf c) is the volume of the parallelepiped.

    ≈ 45 min
AQA 7367 Further vectors — A Level Further Mathematics · Salam Academy