A) 2
B) \[\frac{1}{2}\]
C) \[\frac{1}{3}\]
D) 3
Correct Answer: A
Solution :
Since \[\mathbf{a}\]and \[\mathbf{b}\]are collinear, we have \[\mathbf{a}=m\mathbf{b}\]for some scalar m. Þ \[\mathbf{i}-\mathbf{j}=m\text{ }(-2\mathbf{i}+k\mathbf{j})\]Þ \[\mathbf{i}-\mathbf{j}=-2m\mathbf{i}+km\mathbf{j}\] Þ \[-2m=1,\,km=-1\] \ \[m=-\frac{1}{2},\] So \[k=2\].You need to login to perform this action.
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