$\mathbf{a}=\begin{pmatrix}4\\1\end{pmatrix}$ and $\mathbf{b}=\begin{pmatrix}2\\-5\end{pmatrix}$.
Write as column vectors:
(a) $3\mathbf{a}$ [1]
(b) $\mathbf{a}-\mathbf{b}$ [1]
(c) $\mathbf{a}+2\mathbf{b}$ [1]
- (a) $\begin{pmatrix}12\\3\end{pmatrix}$B1
- (b) $\begin{pmatrix}2\\6\end{pmatrix}$B1
- (c) $\begin{pmatrix}8\\-9\end{pmatrix}$B1
- Answer: (a) $\begin{pmatrix}12\\3\end{pmatrix}$ (b) $\begin{pmatrix}2\\6\end{pmatrix}$ (c) $\begin{pmatrix}8\\-9\end{pmatrix}$
- Examiner tip: Take care with subtracting a negative: $1-(-5)=6$.