If a = i - 2j and b = 2i + j are parallel, then is - Vidyadip

MCQ

If $a = i - 2j$ and $b = 2i + \lambda j$ are parallel, then $\lambda $ is

A
$4$
B
$2$
C
$-2$
✓
$-4$

✓

Answer

Correct option: D.

$-4$

d
(d) $\frac{1}{2} = \frac{{ - 2}}{\lambda } \Rightarrow \lambda = - 4$.

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