1.3: Column vectors: equal moduli and comparing components

0606/12/M/J/16 — Question 3 · 6 marks

Vectors a\mathbf{a}, b\mathbf{b} and c\mathbf{c} are such that a=(2y)\mathbf{a} = \begin{pmatrix} 2 \\ y \end{pmatrix}, b=(13)\mathbf{b} = \begin{pmatrix} 1 \\ 3 \end{pmatrix} and c=(55)\mathbf{c} = \begin{pmatrix} -5 \\ 5 \end{pmatrix}.
(i)
Given that a=bc|\mathbf{a}| = |\mathbf{b} - \mathbf{c}|, find the possible values of yy.
[3]
(ii)
Given that μ(b+c)+4(bc)=λ(2bc)\mu(\mathbf{b} + \mathbf{c}) + 4(\mathbf{b} - \mathbf{c}) = \lambda(2\mathbf{b} - \mathbf{c}), find the value of μ\mu and of λ\lambda.
[3]