If $|\mathbf{a}| = 4$ and $-3 \le \lambda \le 2$, then the range of $|\lambda \mathbf{a}|$ is |
$[0, 8]$ $[-12, 8]$ $[0, 12]$ $[8, 12]$ |
$[0, 12]$ |
The correct answer is Option (3) → $[0, 12]$ ## We have, $|\mathbf{a}| = 4$ and $-3 \le \lambda \le 2$ $∴|\lambda \mathbf{a}| = |\lambda| |\mathbf{a}| = \lambda \cdot 4$ $\Rightarrow |\lambda \mathbf{a}| = |-3| \cdot 4 = 12, \text{ at } \lambda = -3$ $|\lambda \mathbf{a}| = |0| \cdot 4 = 0, \text{ at } \lambda = 0$ and $|\lambda \mathbf{a}| = |2| \cdot 4 = 8, \text{ at } \lambda = 2$ So, the range of $|\lambda \mathbf{a}|$ is $[0, 12]$. |