Jika \(k\) adalah suatu skalar, maka hasil perkalian \(k\) dengan suatu vektor \(\textbf{r} = \left(\begin{array}{c}x\\ y\end{array}\right)\) adalah \(\left(\begin{array}{c}kx\\ ky\end{array}\right)\)
Contoh Soal
Soal 1 Tentukan hasil dari \(-2\left(\begin{array}{c}1\\ -5\end{array}\right)\)
\(-2\left(\begin{array}{c}1\\ -5\end{array}\right) =\left(\begin{array}{c}-2\times 1\\ -2\times (-5)\end{array}\right) \)
\(-2\left(\begin{array}{c}1\\ -5\end{array}\right) =\left(\begin{array}{c}-2\\ 10\end{array}\right) \)
Soal 2
Jika \(k\left(\begin{array}{c}2\\ m\end{array}\right) = \left(\begin{array}{c}6\\ -12\end{array}\right)\), tentukan nilai \(k + m\)
\(\left(\begin{array}{c}2k\\ mk\end{array}\right) = \left(\begin{array}{c}6\\ -12\end{array}\right)\)
\(2k = 6 \)
\(k = 3\)
\(mk = -12\)
\(3m = -12\)
\(m = -\frac{12}{3}\)
\(m = -4\)
\(\text{Jadi, nilai } m + k = -4 + 3 = -1\)