A) \[\cos \theta =\frac{4}{21}\]
B) \[\cos \theta =\frac{3}{19}\]
C) \[\cos \theta =\frac{2}{19}\]
D) \[\cos \theta =\frac{5}{21}\]
Correct Answer: A
Solution :
\[\cos \theta =\frac{\mathbf{a}\,.\,\mathbf{b}}{|\mathbf{a}|\,\,\,|\mathbf{b}|}=\frac{12-6-2}{\sqrt{4+4+1}\sqrt{36+9+4}}=\frac{4}{21}\].You need to login to perform this action.
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