N1982 P2 Q4

N1982 P2 Q4

Past Year National Exams
Free
  1. Given that \({2\mathbf{x} + (\mathbf{x} \cdot \mathbf{b})\mathbf{a} = \mathbf{c}}\), where \({\mathbf{a} \cdot \mathbf{b} \neq -2}\), show that \({\mathbf{x} \cdot \mathbf{b} = \frac{\mathbf{c} \cdot \mathbf{b}}{2 + \mathbf{a} \cdot \mathbf{b}}}\).
    Deduce an expression for \({\mathbf{x}}\) in terms of \({\mathbf{a}}\), \({\mathbf{b}}\) and \({\mathbf{c}}\).

Video Solution:

Default solution

  1. List item image
Answer:\(\mathbf{x}=\frac{1}{2}\left[ \mathbf{c}-\left( \frac{\mathbf{c}\cdot \mathbf{b}}{2+\mathbf{a}\cdot \mathbf{b}} \right)\mathbf{a} \right]\)

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