Mathematics for IGCSE & O level - Vectors (Section 1 - No. 19)
Given that \(\vec{a} = \begin{pmatrix} -1 \\ 2 \end{pmatrix}\) and \(\vec{b} = \begin{pmatrix} 3 \\ 1 \end{pmatrix}\), then \(2\vec{a} - \vec{b}\) is equal to:
\(\begin{pmatrix} -5 \\ 3 \end{pmatrix}\)
\(\begin{pmatrix} -5 \\ 5 \end{pmatrix}\)
\(\begin{pmatrix} -4 \\ 0 \end{pmatrix}\)
\(\begin{pmatrix} 1 \\ 5 \end{pmatrix}\)
Explicação
2a-b = 2\(\begin{pmatrix} -1 \\ 2 \end{pmatrix}\) - \(\begin{pmatrix} 3 \\ 1 \end{pmatrix}\) = \(\begin{pmatrix} -2 \\ 4 \end{pmatrix}\) - \(\begin{pmatrix} 3 \\ 1 \end{pmatrix}\) = \(\begin{pmatrix} -5 \\ 3 \end{pmatrix}\)